Compress an Image
Make an image file smaller without an obvious drop in quality. Upload a JPG, PNG or WebP, pick a quality level, and download a lighter version.
Large images are the usual reason a page loads slowly, an email bounces, or an upload form refuses a file. Dropping the quality setting a little typically removes most of the weight while looking identical at normal viewing sizes.
How it works
Filembly re-encodes your image with the quality you choose, using mozjpeg for JPEG output — the same encoder used to optimise images for the web, which produces smaller files than a standard JPEG encoder at matching quality.
Quality between 60 and 80 is the useful range for photographs. Below about 50, compression artefacts start to show in smooth areas like skies and skin.
Switching the output to WebP usually gives a substantially smaller file than JPEG at the same visual quality. Every current browser supports WebP, so it is a safe choice for anything going on the web.
PNG works differently, because it is a lossless format. There the quality setting drives palette quantisation — reducing the number of distinct colours — which is what actually shrinks a PNG.
How to compress image
- Upload the JPG, PNG or WebP image you want to shrink.
- Choose a quality level — 70 is a good starting point.
- Optionally switch the output format to WebP for a bigger saving.
- Click Compress image and download the result.
Limitations to know about
- Compression below roughly 50 quality becomes visible on photographs, particularly in gradients and flat colour areas.
- Pixel dimensions are unchanged. If the image is far larger than it needs to be, resizing it first usually saves much more than compression alone.
- Transparency is lost when the output is JPEG, since the format has no alpha channel — transparent areas are filled with white. Choose PNG or WebP to keep it.
Privacy and security
Your files are uploaded over HTTPS, processed entirely in memory and streamed straight back to your browser. They are never written to disk, never logged and never retained after the response — there is nothing to delete because nothing is stored. Uploads are validated by extension, type and content signature, and are never executed. Read more in our privacy policy.
Frequently asked questions
How much smaller will my image get?
It depends on the original. A photo saved at maximum quality often drops by half or more at quality 70 with no visible difference. Converting the same image to WebP commonly saves substantially more again. Images already optimised will shrink far less.
Will compressing make my image look worse?
At 60 to 80 quality, almost never at normal viewing sizes. JPEG compression is lossy, so quality is genuinely discarded, but it discards detail the eye is least sensitive to first. Below 50 the artefacts become noticeable.
Should I compress or resize?
Resize first if the image is bigger than it needs to be — a 4000px photo displayed at 800px wastes most of its data, and scaling it down saves far more than compression can. Then compress the resized version. The two together give the smallest usable file.
Can I compress a PNG without losing quality?
Only to a point. PNG is lossless, so the real lever is reducing the number of colours stored. That works very well for screenshots, logos and diagrams with flat colour, and poorly for photographs — for those, JPEG or WebP is a much better fit.