7 Best Free Image Compression Tools Compared (2026)
We tested TinyPNG, Squoosh, Pikkx, ShortPixel and more with real images. See actual compression results, privacy comparison, and which tool fits your workflow.
What we're comparing
There are dozens of image compression tools available in 2026. We narrowed it down to the 7 most popular free options and compared them on what actually matters: compression quality, privacy, batch support, and ease of use.
The key distinction is where your images are processed — on a remote server (your files are uploaded) or locally in your browser (your files never leave your device). This matters more than most people realize.
For more information about image optimization best practices, see Google's Web.dev performance guides.
The tools
1. Pikkx
Processing: 100% client-side (WebAssembly in browser) Formats: JPEG, PNG, WebP Batch limit: 10 images per session Extras: Resize, format conversion, quality control
Pikkx processes images entirely in your browser using jSquash WebAssembly codecs. Nothing is uploaded anywhere. You can compress, resize, and convert formats in one step.
Best for: Anyone who wants privacy-first batch compression with format conversion.
2. Squoosh (by Google)
Processing: Client-side (WebAssembly) Formats: JPEG, PNG, WebP, AVIF, JPEG-XL Batch limit: 1 image at a time Extras: Side-by-side comparison, granular codec controls
Squoosh gives you fine-grained control over every compression parameter. The split-view interface lets you compare before and after in real time. Its biggest limitation is no batch processing — you can only work with one image at a time.
Best for: Developers who need precise control over compression settings.
3. TinyPNG
Processing: Server-side (upload required) Formats: PNG, JPEG, WebP Batch limit: 20 images, 5MB each (free tier) Extras: WordPress plugin, developer API
TinyPNG has been the default recommendation for years. It uses smart lossy compression that produces excellent results. The tradeoff is that your images are uploaded to their servers for processing.
Best for: Quick compression when privacy isn't a concern.
4. ShortPixel
Processing: Server-side (upload required) Formats: JPEG, PNG, GIF, WebP, AVIF, PDF Batch limit: 50 images on web tool Extras: Three compression modes (lossy, glossy, lossless), WordPress plugin
ShortPixel consistently produces some of the best compression ratios in testing. It offers three modes: lossy (maximum compression), glossy (balanced), and lossless (no quality loss). It also supports PDF compression, which is unique.
Best for: WordPress sites and users who want multiple compression levels.
5. Compressor.io
Processing: Server-side (auto-delete) Formats: JPEG, PNG, SVG, GIF, WebP Batch limit: 5 files at a time Extras: SVG compression, multiple compression modes
Notable for being one of the few free tools that compresses SVG files. The interface is clean but the 5-file batch limit is restrictive.
Best for: Compressing SVG graphics.
6. ImageOptim (macOS)
Processing: Local desktop app Formats: PNG, JPEG, GIF Batch limit: Unlimited Extras: Lossless by default, metadata removal, multiple engines
ImageOptim is a macOS-only desktop app that runs multiple compression engines (MozJPEG, pngquant, Gifsicle) to find the smallest result. It's lossless by default, so quality is preserved.
Best for: Mac users who need unlimited batch processing offline.
7. Optimizilla
Processing: Server-side (upload required) Formats: JPEG, PNG Batch limit: 20 images Extras: Individual quality slider per image, side-by-side preview
Optimizilla lets you adjust quality per image with a visual preview, which is useful for finding the right balance. Limited format support though — no WebP.
Best for: Visual learners who want to preview compression quality per image.
Feature comparison
Privacy matters more than you think
When you upload images to a server-based tool, you're trusting that service with your files. For personal photos, client work, or proprietary designs, that's a real consideration.
According to Google's performance research, optimized images can significantly improve Core Web Vitals scores.
Client-side tools (Pikkx, Squoosh, ImageOptim) process everything on your device. The images never touch a remote server. You can verify this by disconnecting from the internet after the page loads — the tool still works.
If you're compressing images that contain sensitive information (client mockups, unpublished designs, personal photos), always use a client-side tool. There's no technical reason to upload images for compression.
Which tool should you use?
Want privacy + batch processing? → Pikkx. Process up to 10 images at once, entirely in your browser, with format conversion and resizing built in.
Want maximum control per image? → Squoosh. Unmatched codec controls and visual comparison, but one image at a time.
On a WordPress site? → ShortPixel. Best WordPress integration with automatic optimization on upload.
On a Mac, need offline? → ImageOptim. Unlimited batch, lossless by default, runs locally.
Need an API for automation? → TinyPNG. 500 free API calls per month, well-documented SDKs.
The right tool depends on your workflow. For most web developers who value privacy and need batch processing, a client-side tool is the way to go.
Try Pikkx — free, private, no account
Compress, resize, and convert images in your browser. Your files never leave your device.