7 Best Free Image Compression Tools Compared (2026)
We compared TinyPNG, Squoosh, Pikkx, ShortPixel and more on privacy, formats, batch limits and resizing, so you can see which tool fits your workflow.
What we're comparing
There are dozens of image compression tools available in 2026. We narrowed it down to 7 well-known free options and compared them on what actually matters: privacy, supported formats, batch support, and free-tier limits.
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, HEIC in; JPG, PNG, WebP out (no AVIF yet) Batch limit: 10 images per batch (5MB each), unlimited batches Extras: Resize, format conversion, several sizes in one pass, ZIP download
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: AVIF, WebP, MozJPEG, OxiPNG, JPEG XL, QOI, WebP2 Batch limit: 1 image at a time Extras: Side-by-side comparison, granular codec controls, resize
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, AVIF, JPEG XL (accepts HEIC) Batch limit: 20 images per session, 5MB each (free tier) Extras: Format conversion (3 per session on the free tier), ZIP download, 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, which keep them for up to 48 hours, and the web tool doesn't resize.
Best for: Quick compression when privacy isn't a concern.
4. ShortPixel
Processing: Server-side (upload required) Formats: JPEG, PNG, GIF, PDF (converts to WebP and AVIF) Batch limit: Up to 50 files at a time on the web tool, 10MB each Extras: Three compression modes (lossy, glossy, lossless), resize, WordPress plugin
ShortPixel offers three modes: lossy (maximum compression), glossy (balanced), and lossless (no quality loss). It also compresses PDFs, which few image tools do.
Best for: WordPress sites and users who want multiple compression levels.
5. Compressor.io
Processing: Server-side (says it deletes images after compressing) Formats: JPEG, PNG, SVG, GIF, WebP Free limits: 10MB per file, 50 compressions per day Extras: SVG compression, lossy and lossless modes, ZIP download
Notable for being one of the few free tools that compresses SVG files. The interface is clean, but it doesn't convert formats and resizing is Pro only ($50/year).
Best for: Compressing SVG graphics.
6. ImageOptim (macOS)
Processing: Local desktop app Formats: PNG, JPEG, GIF, SVG 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, Zopfli, SVGO) 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 and others Batch limit: Several images at once 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.
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.