Best Free Image Compression Tools in 2025

What to look for in an image compressor

Before diving into specific tools, here's what actually matters when choosing one:

• Privacy. Does it upload your files to a server? If yes, what are the retention policies? For personal or business images, this matters.
• Quality control. Can you adjust the compression level? A fixed setting means you can't control the trade-off between quality and size.
• Format support. Does it handle JPG, PNG, WebP? Can it convert between formats?
• Batch processing. Can you compress multiple images at once? For large projects, this matters a lot.
• Actual free vs "free". Many tools are free up to a limit, then require a paid plan. Know what you're signing up for.

FreeImageTools.org — Browser-based, fully free

Best for: Individual images, privacy-sensitive content, quick one-off compression.

This is ours, so take this with appropriate scepticism — but here's the honest case for it. FreeImageTools runs entirely in the browser. Your image never leaves your device. There's no account, no sign-up, no watermark, no file size limit on the free tier (because there's only one tier: free).

The trade-off is that it processes one image at a time and doesn't have batch compression. If you need to compress 200 images at once, this isn't the right tool. But for individual images where privacy matters or you just need to quickly squash something down, it's the most straightforward option.

Quality slider from 10-100%. Before/after file size shown. Works on mobile. No ads on the tool itself.

TinyPNG / TinyJPG — The popular choice

Best for: Batch compression, high-quality lossy PNG optimisation.

TinyPNG is widely used and genuinely good at its job. It uses smart lossy compression for PNG files that reduces file size dramatically while keeping visual quality high. The algorithm is excellent — often better than basic compression at the same quality level.

But: it uploads your files to their servers. The free tier limits you to 20 images per batch and 5MB per image. You need an account and API key for larger usage. For high-volume workflows, it's a paid product.

Squoosh — Google's browser-based option

Best for: Technical users who want fine-grained control over compression settings.

Squoosh is built by Google and runs in the browser. Like FreeImageTools, it doesn't upload your files. It supports a wider range of codecs — including AVIF and more experimental formats — and gives you much more granular control over encoding settings.

The downside is the interface. It's built for people who know what “effort level” and “near lossless” mean. For non-technical users, it's more confusing than it needs to be. It also processes one image at a time.

ImageOptim — Mac desktop app

Best for: Mac users who want batch processing without uploads.

ImageOptim is a free Mac app that compresses images locally. It uses multiple compression algorithms (pngcrush, optipng, jpegoptim, and others) and picks the best result. It handles batch processing well.

The limitation is platform: Mac only. If you're on Windows or Linux, this isn't an option. And for occasional one-off compression, a desktop app is more friction than a web tool.

ShortPixel — For WordPress users

Best for: WordPress sites, automatic optimisation on upload.

ShortPixel is a WordPress plugin that automatically compresses images when you upload them to your media library. It's excellent for teams where not everyone is technically minded — compression just happens without anyone having to do anything.

It's a paid service after the free tier (100 images/month). For high-volume WordPress sites, it's worth the cost. For personal sites with modest image counts, the free tier is usually enough.

The honest summary

There's no single “best” tool — it depends what you need. For one image, fast, private, and free: browser-based tools work best. For batch compression of website images: TinyPNG or ShortPixel. For maximum technical control: Squoosh. For Mac batch processing without any uploads: ImageOptim.