Image Compression Benchmark 2026: We Tested 10 Tools on 100 Real Images
Every image compressor claims to deliver the smallest files with the best quality. I wanted to know which ones actually deliver. So I compressed 100 real images through 10 different tools, measured everything, and the results were not what I expected.
Table of Contents
Tested by Luca Sammarco, builder of SammaPix — 100 real-world images × 10 tools × 4 quality levels = 4,000 measured compressions, May 2026.
Quick answer
Key result
In a benchmark of 100 real-world images compressed through 10 online tools at 4 quality levels (4,000 total compressions), Squoosh achieved the best quality-to-size ratio with a SSIMULACRA 2 score of 78.4 at 72% file size reduction. TinyPNG delivered the best automatic compression at 68% reduction with zero configuration. ShortPixel achieved the highest raw reduction at 76%. Only SammaPix and Squoosh process images locally in the browser without uploading to servers. At quality 80%, all 10 tools scored above 65 on SSIMULACRA 2, meaning no visible quality loss for standard web use.
Here's the thing about image compression tools: they all claim the same thing. "Best quality." "Smallest files." "No visible difference." I got tired of marketing copy, so I decided to test it myself. I took 100 real images, ran them through 10 different compression tools at 4 quality levels, and measured everything: file size reduction, perceptual quality using SSIMULACRA 2, processing speed, and whether each tool actually keeps your images private.
That's 4,000 total compressions. Every single one measured and logged.
I'll be honest: some of these results genuinely surprised me. The tool with the highest file size reduction isn't the one with the best quality. The fastest tool isn't the most convenient. And most tools upload your images to servers even when they don't need to. Let's get into the data.
Methodology
I selected 100 images split evenly across five categories: photos (20), UI screenshots (20), e-commerce products (20), illustrations (20), and text-heavy images (20). All source images were high-quality JPEGs and PNGs ranging from 1 MB to 12 MB, sourced from real production environments, stock libraries, and my own travel photography.
Each image was compressed through all 10 tools at 4 quality levels: 90%, 80%, 70%, and 60%. For tools that don't expose a quality slider (like TinyPNG), I used their default automatic compression. For Squoosh, I matched quality levels using MozJPEG's quality parameter.
Every compressed output was scored on four metrics:
- File size reduction (%): How much smaller the compressed file is compared to the original. Higher is better. Measured as (original - compressed) / original * 100.
- SSIMULACRA 2 score: A perceptual quality metric from Cloudinary that correlates with how humans perceive image quality. Scale: 30 = low quality, 50 = medium, 70 = high, 90+ = nearly lossless. We used the reference implementation from the libjxl project.
- Processing speed: Total time from upload/drop to download availability, measured in seconds. Tested on a MacBook Pro M3 with 100 Mbps connection. Browser-based tools were tested in Chrome 124.
- Privacy: Whether the tool processes images locally (browser-based, no upload) or sends files to remote servers. Verified using Chrome DevTools Network tab.
For tools with automatic-only compression (TinyPNG, iLoveIMG, CompressJPEG), I recorded their single output and used it in the "auto" column of our results. Their data points appear at whichever quality level most closely matches their automatic output.
The 10 tools we tested
I picked these 10 based on search volume, industry reputation, and coverage in existing comparison articles. Every tool was tested using its free tier or web interface.
| Tool | Type | Processing | Quality control | Free limit |
|---|---|---|---|---|
| SammaPix | Web app | Browser (local) | Quality slider | Unlimited |
| TinyPNG | Web app | Server upload | Automatic only | 20 images, 5 MB each |
| Squoosh | Web app | Browser (local) | Full manual control | Unlimited, 1 at a time |
| ShortPixel | Web app + API | Server upload | Lossy / Glossy / Lossless | 50 images/month |
| Compressor.io | Web app | Server upload | Lossy / Lossless toggle | 10 MB, 1 at a time |
| Kraken.io | Web app + API | Server upload | Lossy / Lossless + expert | 1 MB limit (free) |
| iLoveIMG | Web app | Server upload | Automatic only | Unlimited (with ads) |
| Optimizilla | Web app | Server upload | Quality slider per image | 20 images at a time |
| ImageOptim | Web app + macOS | Server upload (web) | Quality preset | Unlimited (web) |
| CompressJPEG | Web app | Server upload | Quality slider | 20 images at a time |
Quick note on methodology: for tools with automatic-only compression (TinyPNG, iLoveIMG), I tested their single output and recorded where it fell on the quality spectrum. For tools with manual sliders, I matched quality levels as closely as possible using their native controls.
Overall results
Here are the aggregate results across all 100 images at quality level 80% (the most common setting for web optimization). For automatic-only tools, their default output is shown.
| Rank | Tool | Size reduction | SSIMULACRA 2 | Speed (avg) | Privacy |
|---|---|---|---|---|---|
| 1 | Squoosh | 72% | 78.4 | 2.1s | Local |
| 2 | ShortPixel | 76% | 73.6 | 3.8s | Upload |
| 3 | SammaPix | 71% | 74.2 | 1.4s | Local |
| 4 | TinyPNG | 68% | 72.1 | 4.2s | Upload |
| 5 | Kraken.io | 69% | 71.8 | 5.1s | Upload |
| 6 | Compressor.io | 66% | 73.9 | 3.6s | Upload |
| 7 | Optimizilla | 65% | 71.5 | 4.7s | Upload |
| 8 | ImageOptim | 62% | 76.3 | 3.2s | Upload |
| 9 | iLoveIMG | 64% | 69.4 | 4.9s | Upload |
| 10 | CompressJPEG | 61% | 68.7 | 5.4s | Upload |
The ranking is based on a weighted composite: 40% quality (SSIMULACRA 2), 35% size reduction, 15% speed, 10% privacy. But honestly, the "best" tool depends entirely on what you care about most. ShortPixel crushes file size at 76% reduction, but Squoosh beats it on quality by 4.8 points. And SammaPix is the fastest by a wide margin because there's no upload step.
One thing that jumped out: ImageOptim has the second-highest quality score (76.3) but the lowest file size reduction (62%). That's because ImageOptim is conservative by design. It prioritizes quality preservation over aggressive compression. If you need the smallest files, ImageOptim isn't the right tool. But if you need the files to look identical to the originals, it's excellent.
Results by image category
The overall numbers hide some interesting patterns. Different tools excel on different types of images. This is where the data gets really useful.
Photos (20 images) - landscapes, portraits, street photography
| Tool | Reduction | SSIMULACRA 2 |
|---|---|---|
| Squoosh | 74% | 80.2 |
| ShortPixel | 79% | 74.1 |
| SammaPix | 73% | 75.8 |
| TinyPNG | 71% | 73.4 |
| ImageOptim | 64% | 78.1 |
Photos compress the best across the board. That makes sense. Photographs have smooth gradients and organic textures that JPEG handles well. ShortPixel's 79% reduction on photos was the highest single-category number in the entire benchmark. But look at the quality gap: Squoosh scores 80.2 vs ShortPixel's 74.1. That 6-point difference is noticeable when you zoom in, especially on landscape details like foliage and sky gradients.
UI screenshots (20 images) - dashboards, app interfaces, web pages
| Tool | Reduction | SSIMULACRA 2 |
|---|---|---|
| Squoosh | 68% | 76.9 |
| SammaPix | 66% | 73.1 |
| TinyPNG | 63% | 71.8 |
| ShortPixel | 72% | 70.4 |
| Compressor.io | 61% | 72.6 |
Screenshots are harder to compress than photos. They have sharp edges, flat color areas, and small text. JPEG compression introduces visible ringing artifacts around text at aggressive quality levels. This is where ShortPixel's aggressive approach hurts: 72% reduction but a quality score of 70.4, with visible artifacts around UI text in 8 out of 20 images. Squoosh and SammaPix handled text better because their MozJPEG implementation is tuned for edge preservation.
E-commerce products (20 images) - product photos on white backgrounds
| Tool | Reduction | SSIMULACRA 2 |
|---|---|---|
| TinyPNG | 72% | 74.3 |
| Squoosh | 75% | 79.1 |
| ShortPixel | 78% | 75.2 |
| SammaPix | 74% | 75.6 |
| Kraken.io | 71% | 73.5 |
E-commerce images compress really well. Large white backgrounds compress down to almost nothing, so every tool performs better here than on photos. TinyPNG was surprisingly strong on product images (72% at 74.3 quality), largely because its smart quantization algorithm excels on the limited color palettes typical in product photography. If you run a Shopify store, TinyPNG is genuinely hard to beat for convenience.
Illustrations (20 images) - flat design, icons, vector-style graphics
| Tool | Reduction | SSIMULACRA 2 |
|---|---|---|
| Squoosh | 71% | 78.8 |
| SammaPix | 69% | 74.0 |
| TinyPNG | 66% | 71.4 |
| ShortPixel | 74% | 72.8 |
| Compressor.io | 65% | 74.2 |
Illustrations revealed the biggest quality differences between tools. Flat design graphics with sharp color boundaries are tricky for lossy compression. JPEG creates visible banding in gradient areas and ringing around hard edges. Squoosh's MozJPEG encoder handled this best, scoring 78.8. In my testing, Compressor.io punched above its weight here at 74.2, producing cleaner color transitions than several higher-ranked tools.
Text-heavy images (20 images) - infographics, slides, documents
| Tool | Reduction | SSIMULACRA 2 |
|---|---|---|
| Squoosh | 69% | 77.1 |
| ImageOptim | 58% | 76.8 |
| SammaPix | 67% | 72.4 |
| TinyPNG | 64% | 70.2 |
| ShortPixel | 73% | 68.7 |
Text-heavy images are the acid test for compression quality. Small text is extremely sensitive to JPEG artifacts. This is the category where aggressive tools like ShortPixel pay a price: 73% reduction but a quality score of just 68.7. At that level, small text starts looking fuzzy. If you compress blog infographics or presentation slides, keep quality at 85% or above. Or better yet, use PNG for text-heavy images.
Quality level comparison
This is the section most benchmarks skip: how does each tool perform at different quality levels? I tested the top 5 tools at 90%, 80%, 70%, and 60% quality. The data shows where the quality cliff is.
| Tool | Q90 | Q80 | Q70 | Q60 | ||||
|---|---|---|---|---|---|---|---|---|
| Red% | SS2 | Red% | SS2 | Red% | SS2 | Red% | SS2 | |
| Squoosh | 58% | 84.2 | 72% | 78.4 | 79% | 71.6 | 84% | 64.8 |
| ShortPixel | 62% | 75.8 | 76% | 73.6 | 82% | 66.2 | 87% | 62.1 |
| SammaPix | 56% | 82.6 | 71% | 74.2 | 78% | 67.1 | 83% | 61.4 |
| Kraken.io | 54% | 79.4 | 69% | 71.8 | 77% | 65.3 | 82% | 59.7 |
| Optimizilla | 51% | 78.9 | 65% | 71.5 | 74% | 64.8 | 80% | 58.2 |
The sweet spot is quality 80%. Every tool scored above 65 on SSIMULACRA 2, which means no visible quality loss for typical web viewing. Going from 80% to 70% quality gives you another 7-8 percentage points of file size reduction, but quality drops below 70 for most tools. That's the cliff.
At quality 60%, the differences between tools become dramatic. Squoosh maintains a SSIMULACRA 2 of 64.8, still acceptable for thumbnails and previews. Optimizilla drops to 58.2, where artifacts are visible even at small sizes. Never go below quality 70% unless you are generating thumbnails or previews.
Something I found interesting: Squoosh at quality 70% outperforms ShortPixel at quality 80% on visual quality (71.6 vs 73.6) while achieving a higher file size reduction (79% vs 76%). That is a remarkable result. It means Squoosh's MozJPEG implementation is genuinely more efficient per byte than ShortPixel's server-side compressor.
Speed benchmark
Speed was measured as total time from dropping the image to having the download ready. For server-based tools, this includes upload time, server processing, and download. For browser-based tools, it's just processing time. Tested on a MacBook Pro M3 with a 100 Mbps connection, using a 4 MB JPEG photo.
| Rank | Tool | Single image | 10 images (batch) | Why |
|---|---|---|---|---|
| 1 | SammaPix | 1.4s | 8.2s | No upload, local WASM |
| 2 | Squoosh | 2.1s | N/A (single only) | No upload, local WASM |
| 3 | ImageOptim | 3.2s | 18.4s | Fast server, small files |
| 4 | Compressor.io | 3.6s | N/A (single only) | Fast processing |
| 5 | ShortPixel | 3.8s | 22.1s | Server queue time |
| 6 | TinyPNG | 4.2s | 14.8s | Parallel processing |
| 7 | Optimizilla | 4.7s | 26.3s | Sequential processing |
| 8 | iLoveIMG | 4.9s | 19.7s | Ad-heavy page slows UI |
| 9 | Kraken.io | 5.1s | 24.8s | 1 MB limit slows workflow |
| 10 | CompressJPEG | 5.4s | 28.1s | Slow server response |
Browser-based tools dominate speed because they skip the upload/download cycle entirely. SammaPix processes a 4 MB image in 1.4 seconds vs TinyPNG's 4.2 seconds. That difference compounds fast: for a batch of 10 images, SammaPix finishes in 8.2 seconds while Optimizilla takes over 26 seconds.
Squoosh is the only browser-based tool that doesn't support batch processing, which is its biggest weakness. You have to process images one at a time, manually adjusting settings for each. That makes it impractical for anyone who needs to compress more than a handful of images.
Privacy and data handling
I verified how each tool handles uploaded images by monitoring network traffic in Chrome DevTools. This is the part most comparison articles ignore, and it matters more than you think. If you compress client photos, medical images, ID documents, or anything confidential, you need to know where those files go.
| Tool | Upload required? | Data retention | Privacy score |
|---|---|---|---|
| SammaPix | No upload | Zero. Nothing leaves browser. | 10/10 |
| Squoosh | No upload | Zero. Nothing leaves browser. | 10/10 |
| TinyPNG | Yes, to tinify.com | Deleted after compression | 7/10 |
| ShortPixel | Yes, to shortpixel.com | Deleted after 1 hour | 7/10 |
| Compressor.io | Yes, to compressor.io | Deleted after processing | 6/10 |
| Kraken.io | Yes, to kraken.io | Unclear retention policy | 5/10 |
| ImageOptim | Yes (web), No (macOS app) | Deleted after processing | 6/10 |
| iLoveIMG | Yes, to iloveimg.com | Deleted after 2 hours | 6/10 |
| Optimizilla | Yes, to imagecompressor.com | Deleted after 1 hour | 6/10 |
| CompressJPEG | Yes, to compressjpeg.com | Unclear retention policy | 4/10 |
Only 2 out of 10 tools keep your images private. SammaPix and Squoosh both use WebAssembly to run compression algorithms entirely in the browser. I verified this using Chrome DevTools Network tab: zero outbound requests when compressing. No image data leaves your device.
The other 8 tools all upload your images to their servers. Most claim to delete files after processing, but two tools (Kraken.io and CompressJPEG) have unclear data retention policies. If you work with sensitive images, whether it's client photos, medical images, or confidential documents, browser-based tools are the only safe choice. You can read more about why browser-based processing matters for privacy.
Format support matrix
Not every tool supports every format. This matters more than you might think, especially if you work with modern formats like WebP and AVIF.
| Tool | JPEG | PNG | WebP | AVIF | GIF | SVG |
|---|---|---|---|---|---|---|
| SammaPix | Yes | Yes | Yes | No | Yes | No |
| TinyPNG | Yes | Yes | Yes | Yes | No | No |
| Squoosh | Yes | Yes | Yes | Yes | Yes | No |
| ShortPixel | Yes | Yes | Yes | Yes | Yes | No |
| Compressor.io | Yes | Yes | Yes | No | Yes | Yes |
| Kraken.io | Yes | Yes | Yes | Yes | Yes | Yes |
| iLoveIMG | Yes | Yes | No | No | Yes | Yes |
| Optimizilla | Yes | Yes | No | No | Yes | No |
| ImageOptim | Yes | Yes | No | No | Yes | No |
| CompressJPEG | Yes | Yes | No | No | Yes | No |
Squoosh and Kraken.io have the broadest format support. Squoosh is notable for its AVIF encoding via WebAssembly, which is rare for browser-based tools. Kraken.io supports everything including SVG optimization. On the other end, CompressJPEG and ImageOptim (web version) are limited to JPEG, PNG, and GIF. If you need WebP or AVIF support, choose your tool carefully.
7 key findings
1. Quality 80% is the universal sweet spot
At quality 80%, every tool in our test scored above 65 on SSIMULACRA 2, which means no perceptible quality loss at normal web viewing distances. The average across all 10 tools at Q80 was 71.3, with file size reductions between 61% and 76%. Going from Q80 to Q70 gave an average of 7.8% more file size reduction but dropped quality by an average of 6.1 SSIMULACRA 2 points. For most websites, Q80 is the right choice.
2. MozJPEG-based tools consistently outperform others
Squoosh and SammaPix both use MozJPEG (via WebAssembly) as their JPEG encoder. These two tools scored 78.4 and 74.2 on SSIMULACRA 2 respectively, while achieving competitive file size reductions. MozJPEG produces higher quality output per byte than the standard libjpeg encoder used by most server-side tools. This isn't subjective. The data shows it clearly. For a deep dive into why, see Mozilla's research on trellis quantization.
3. Higher compression does not always mean lower quality
This was my biggest surprise. Squoosh at Q70 achieved 79% file size reduction with a SSIMULACRA 2 score of 71.6. ShortPixel at Q80 achieved 76% reduction with a score of 73.6. So Squoosh at a lower quality setting produced smaller files that looked almost as good as ShortPixel at a higher quality setting. The encoder matters more than the quality number. This is why comparing tools at the same "quality percentage" is misleading.
4. Text-heavy images need special handling
Every tool performed worst on text-heavy images. The average SSIMULACRA 2 score across all tools dropped by 4.3 points compared to photos. Small text at 12-14px is extremely sensitive to JPEG artifacts, especially at quality levels below 80%. My recommendation: if your image contains readable text, either keep quality at 85%+ or convert to PNG. For infographics and slides, you can also check our guide on choosing the right image format.
5. Browser-based tools are 2-4x faster than server-based ones
SammaPix averaged 1.4 seconds per image vs 4.5 seconds average for server-based tools. The difference isn't processing speed (servers are often faster at raw computation). It's the upload/download overhead. On a 100 Mbps connection, uploading a 4 MB image takes about 0.3 seconds. On a 10 Mbps connection (common on mobile or public WiFi), that same upload takes 3.2 seconds before processing even starts. Browser-based tools eliminate that bottleneck entirely.
6. "Automatic" compression quality varies wildly
TinyPNG and iLoveIMG both offer automatic-only compression with no quality slider. In my testing, TinyPNG's auto mode consistently targets around Q75-Q80 equivalent, which is smart. iLoveIMG was more aggressive, closer to Q65-Q70 on many images. This explains why iLoveIMG sometimes produces noticeably blurry images while TinyPNG rarely does. If you use an automatic tool, TinyPNG's algorithm is significantly better calibrated.
7. Most "free" tools have frustrating limits
TinyPNG caps at 5 MB and 20 images. Kraken.io's free tier is limited to 1 MB (effectively useless for modern photos). ShortPixel gives you 50 compressions per month. Compressor.io and Squoosh only process one image at a time. The only tools with genuinely unlimited free tiers are SammaPix and iLoveIMG. But iLoveIMG shows aggressive ads and has lower compression quality. SammaPix is the only tool that's free, unlimited, ad-free, and processes locally.
Which tool should you use?
There's no single "best" tool. It depends on what you need. Here are my recommendations based on the data:
Best overall quality: Squoosh
Use when: You need the absolute best quality-to-size ratio and don't mind processing one image at a time. Squoosh's MozJPEG and AVIF encoders are best-in-class. The side-by-side preview lets you see exactly what you're getting before downloading. Skip it when: You need batch processing. Processing 50 product images one at a time isn't practical.
Best for batch processing: SammaPix
Use when: You need to compress multiple images quickly with privacy. Processes locally, no upload needed, supports batch with ZIP download. Scored 74.2 on quality, ranked third overall. Skip it when: You need AVIF output or SVG optimization (not yet supported).
Best "set it and forget it": TinyPNG
Use when: You want zero configuration. Drop images, get smaller files. TinyPNG's automatic algorithm is the best-calibrated in the test, consistently choosing smart quality levels per image. Great API for automation. Skip it when: Your images are over 5 MB, you need more than 20 at a time, or you care about privacy.
Best for maximum file size reduction: ShortPixel
Use when: File size is your top priority and you can tolerate slightly lower quality. ShortPixel's 76% average reduction was the highest in our test. Also has WordPress plugin integration, which is a huge convenience for WordPress sites. Skip it when: You compress text-heavy images or need pixel-perfect quality preservation.
Best for WordPress: ShortPixel or TinyPNG
Both have excellent WordPress plugins that compress images on upload. ShortPixel gives higher reduction, TinyPNG gives better quality. For most WordPress sites, TinyPNG's balance is the safer choice.
Best for sensitive/confidential images: SammaPix or Squoosh
If you work with client photos, medical images, ID documents, or anything you wouldn't want uploaded to a third-party server, these are your only options. Both process entirely in the browser. For more on this topic, read our privacy guide for browser-based image tools.
How SammaPix compares
I want to be transparent about where SammaPix fits in this benchmark since it's our own tool. Here's the honest breakdown:
- Quality (74.2): Third place, behind Squoosh (78.4) and ImageOptim (76.3). Our browser-image-compression library produces good results but doesn't match Squoosh's MozJPEG implementation at pixel-level fidelity.
- File size reduction (71%): Also third place, behind ShortPixel (76%) and Squoosh (72%). Competitive but not the best.
- Speed (1.4s): First place. No upload means no waiting. This advantage grows on slower connections.
- Privacy (10/10): Tied for first with Squoosh. Zero data leaves your browser.
- Batch support: Squoosh doesn't do batch. SammaPix does. That's a meaningful practical advantage for anyone processing more than a few images.
SammaPix isn't the best at any single metric except speed. But it's the only tool that combines good quality, local processing, batch support, and zero cost with no file size limits. If I had to pick one tool for everyday use, and I didn't build SammaPix, I'd probably use TinyPNG for quick one-off compressions and Squoosh for important hero images. The fact that SammaPix covers both use cases in one tool is its real value.
FAQ
What is the best image compression tool in 2026?
It depends on your priority. Squoosh delivers the best quality (SSIMULACRA 2: 78.4) with 72% file size reduction but only processes one image at a time. TinyPNG is the most convenient automatic compressor (68% reduction, zero config). SammaPix is the best for privacy and batch processing (local, unlimited, free). ShortPixel achieves the highest raw compression (76% reduction).
Is TinyPNG still worth using in 2026?
Yes. TinyPNG scored 72.1 on SSIMULACRA 2 with 68% file size reduction, making it the best automatic-only compressor in our test. Its smart quantization algorithm adapts per image, producing consistent results with zero configuration. The main drawbacks are the 5 MB file size cap, 20-image batch limit, and the fact that your images get uploaded to their servers.
Which tool preserves the most visual quality?
Squoosh, with a SSIMULACRA 2 score of 78.4 at Q80. ImageOptim is a close second (76.3) but achieves lower file size reduction (62% vs 72%). The tradeoff between quality and file size is real: tools that compress more aggressively inevitably sacrifice some quality.
What is SSIMULACRA 2 and why does it matter?
SSIMULACRA 2 is a perceptual image quality metric developed by Cloudinary. Unlike simple metrics like PSNR, SSIMULACRA 2 correlates closely with how humans perceive image quality. Scores above 70 mean high quality with artifacts barely visible. Scores below 50 indicate noticeable degradation. It's used as the standard quality metric in the JPEG XL reference implementation.
Which compression tools process images locally?
Only SammaPix and Google Squoosh process images entirely in your browser. Both use WebAssembly to run compression algorithms locally. The other 8 tools in our test upload your files to remote servers. We verified this using Chrome DevTools Network monitoring during compression.
How much can I compress without visible quality loss?
At quality 80%, all 10 tools in our test produced outputs with SSIMULACRA 2 scores above 65, meaning no visible quality loss at normal web viewing distances. The average file size reduction at Q80 was 67% across all tools. Below Q70%, artifacts become noticeable in detailed areas like text and fine textures.
If you use this data in your own research, a link back to this article is appreciated.