Free Image Compressor Online

What is image compression?

Image compression shrinks a photo's file size by removing data the eye barely notices — or, for lossless formats, by encoding the same pixels more efficiently. A 4 MB phone photo can usually become a 300–600 KB web image with no visible difference, which means pages load faster, emails send instantly, and uploads stop hitting size limits. This free image compressor online does the whole job in your browser: no uploads, no accounts, no watermarks.

Two kinds of compression matter here. Lossy compression (JPG, WebP, AVIF) discards fine detail in exchange for much smaller files — the quality slider controls how much. Lossless compression (PNG) keeps every pixel exactly but can only squeeze so far, which is why PNG photos barely shrink and should usually be converted to JPG or WebP for the web.

Which format should you choose?

If you only need to change a file's format without compressing, the WebP to JPG converter handles that one job directly.

What quality setting should you use?

Why do some images barely shrink — or get bigger?

An already-optimized image (a photo exported from Lightroom at 80% quality, a screenshot saved by an app that already compressed it) has little redundancy left to remove — the compressor may only shave a few percent. And a re-encode can occasionally come out larger, for example when a small PNG is converted at high quality. This tool is honest about both cases: if the same-format result would be larger than the original, it keeps the original file and tells you, instead of handing you a worse file and calling it “compressed”.

Resizing is the other lever that always works: a 4000px-wide phone photo displayed at 1200px on a page carries four times the pixels it needs. Set a max width and the file size drops with the dimensions — combine it with WebP output and the savings compound. For precise crops before compressing, use the AI smart image cropper, and for stripping location data from photos you plan to share, the image metadata cleaner removes EXIF without touching pixels.

Compressing images for your website

Page speed is a ranking factor and a conversion factor: every extra megabyte of images delays first paint, hurts Core Web Vitals (especially Largest Contentful Paint), and costs mobile visitors data. The practical workflow is: resize to the display width, encode as WebP at 80–85%, and confirm with the compare slider that nothing visible was lost. For a full-page check afterwards, run the website health checker, and when a compressed image needs to go into a document, the image to PDF converter finishes the job. Browse the full image tools collection for the rest of the workflow.

Common mistakes to avoid

• Compressing PNG photos and expecting miracles. PNG is lossless — convert to JPG or WebP (or use Auto mode) for photos.
• Uploading 4000px images to a 1200px slot. Resize first; quality settings alone cannot fix oversized dimensions.
• Judging quality on a thumbnail. Use the compare slider at full size — artifacts hide in small previews and appear in print or zoom.
• Forgetting transparency. Auto mode may convert a transparent PNG to JPG (which has no transparency and fills it white). Choose PNG output when transparency matters.
• Sharing originals with EXIF intact. Phone photos carry GPS locations — this tool strips metadata on every encode, but check other tools you use do the same.