Resize Image by File Size

Resize an image to a target file size

Some forms, marketplaces, email systems and application portals ask for an image under a specific number of kilobytes. Guessing the right dimensions and quality can be frustrating because every photo compresses differently. This resize by file size tool automates the trial and error. Add an image, enter the target KB value, choose JPG or WebP, and the browser searches for a result that fits under the limit while keeping as much visual quality and resolution as it can.

The optimizer is fully client-side. It decodes your image locally, renders it to canvas, tests a compressed Blob size, and repeats with lower quality or smaller dimensions until the output is under the target when possible. Your file is never uploaded to a server, which keeps personal documents, profile photos, IDs, product drafts and client images private. The original file is not changed; you download a new optimized copy.

How quality and scaling work together

The tool starts by reducing encoder quality because that often cuts a large amount of size without changing image dimensions. If the file is still too large, it gradually scales the image down and tries again. This two-step approach usually looks better than immediately shrinking the photo to a tiny resolution. Very aggressive targets may still require visible compression or small dimensions, especially for detailed photos, noisy images or graphics with many sharp edges.

Choosing JPG or WebP

JPG is the safest choice for forms and older systems because it is accepted almost everywhere. WebP often produces smaller files at similar visual quality, making it a strong choice for modern websites and apps. If a site specifically asks for JPG, choose JPG even if WebP would be smaller. Start with a realistic target: lowering a multi-megabyte photo to a few hundred KB usually works well, while forcing it below 20 KB may leave only a very small preview-quality image.