Compress GIF images

GIF is lossless, which means there is no quality dial to turn. The way to make a GIF genuinely smaller is either to reduce its dimensions or to move it to a format with real compression. This tool does both, and shows you what each option costs.

Compression runs entirely in your browser. Nothing is uploaded, there is no file count limit, and you can drop in a whole folder at once.

How the size search works

Image compressors do not take a file size as input. They take a quality number between 1 and 100, and the file size that comes out the other end depends on the picture itself — a photo of a busy street compresses very differently from a photo of a clear sky. That is why setting "quality 60" and hoping is such an unreliable way to hit a limit.

This tool encodes your image repeatedly and narrows in with a binary search: it tries the middle of the range, sees whether the result is above or below your target, and halves the search space each time. After six to nine encodes it has found the highest quality setting that still fits inside your limit. On a typical photograph the whole process finishes in a fraction of a second, because the encoding runs on your own processor rather than waiting in a queue on somebody's server.

If the smallest possible quality still overshoots — which happens when a very large image is pushed towards a very small limit — the tool switches to reducing the dimensions instead, and tells you it did so. Given the choice between a smeared 4000-pixel image and a clean 800-pixel one at the same file size, the clean one is almost always the better answer.

Getting a good result at a small size

• Crop before you compress. Every pixel you remove is a pixel the compressor no longer has to spend bits on. Cropping to just the subject is the single most effective thing you can do.
• Match the dimensions to the use. A passport photo displayed at 413x531 does not need to be 4000 pixels wide. Resizing first frees the whole budget for the pixels that remain.
• Use JPG for photographs. PNG is lossless and will not shrink meaningfully. If your file is a photo and the form accepts JPG, use it.
• Keep PNG for text and screenshots. Sharp black-on-white text develops ugly halos under aggressive JPG compression. If the form allows PNG, screenshots belong there.
• Do not compress twice. Compressing an already-compressed JPG loses more each time. Go back to the original if you still have it.

Your files stay on your device

The images people compress to a fixed size are rarely casual: passport photographs, signatures, bank statements, medical certificates, exam admit cards. Those are exactly the files you should be most reluctant to upload to an anonymous website.

Nothing here is uploaded. The compression runs in your browser using the same encoders your browser uses to save images, so your document never leaves the machine you are sitting at. Open the Network tab in your developer tools and watch — you will not see your file go anywhere, because there is nowhere for it to go.