Image Compression Benchmark 2026: We Tested 10 Tools on 100 Real Images

Tested by Luca Sammarco, builder of SammaPix — 100 real-world images × 10 tools × 4 quality levels = 4,000 measured compressions, May 2026.

Quick answer

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.

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.

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

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

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

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

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

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.

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.

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.

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.

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

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:

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

If you use this data in your own research, a link back to this article is appreciated.