Image Converter and Compressor
Convert and compress images to WebP, AVIF, JPEG or PNG in your browser, resize to a maximum width and compare the file size before and after.
Free · No sign-up · Your inputs stay in your browser
Input
Convert, resize and compress images
Output
Choose an image
Encoded by this browser's own image codecs, so the file is never uploaded. WebP at quality 75-85 is usually a quarter to a half the size of the JPEG it replaces with no visible loss; AVIF goes further but encodes slowly and only some browsers can create it. Re-encoding a JPEG always loses a little: convert from the original, not from a previous export.
Runs in this browser. Nothing you paste is sent to a server.
About this tool
Method, assumptions, practical next steps, and limits.
Which format
WebP at quality 75 to 85 is typically far smaller than a JPEG of similar visual quality and is supported by every current browser. AVIF compresses further but encodes slowly, and only some browsers can encode it in a canvas. PNG is for screenshots, flat graphics and anything needing exact pixels. web.dev's guide to choosing an image format compares them.
Resize first
The biggest saving is usually dimensions, not codec: a 4000-pixel photo shown 800 pixels wide wastes most of its bytes. Serve several sizes with srcset so phones download the small one.