Resize an image to 100 KB

Where 100 KB limits show up

Upload limits around 100 KB are common wherever a site stores a lot of small images: profile and avatar photos on job and education platforms, photo fields on application forms, school and club registrations, some e-commerce and listing sites, and older systems that were built when bandwidth was expensive. A phone photo, at 2 to 5 MB, is twenty to fifty times over.

How it fits the photo under 100 KB

There are two levers, and the order matters. Lowering JPEG quality throws away fine detail; lowering the pixel count throws away resolution. Done badly, you get a large but blocky image, or a tiny but clean one.

The tool starts from a size that a 100 KB file can hold well, then searches the JPEG quality, encoding and measuring the real file each time, until it finds the best quality under 100,000 bytes. If even low quality is too big at that size, it makes the image a step smaller and searches again. The result is the biggest, cleanest image that fits.

If the site asks for exact pixels, say 400 × 400 for a profile photo, switch Dimensions to Pixels and type them in. The crop box takes that shape, you frame what matters, and the KB search works on that exact size. At 400 × 400, 100 KB is generous and the photo stays sharp.

Reading the limit safely

A 100 KB limit can mean 100,000 bytes or 102,400, depending on how the site counts. The tool keeps under 100,000, so the file passes everywhere. If the site also has a minimum, type it in Min: a file that comes out smaller than the minimum gets empty bytes added inside the JPEG to reach it, and the page tells you. The guide to KB and KiB explains both.

Getting a better result

Crop first. Cutting away background you don't need leaves more of the 100 KB for what you keep.

Good light, less noise. A photo taken in daylight compresses far better than a dim one, whose grainy noise eats bytes.

JPG, not PNG. For photographs, JPEG is many times smaller than PNG at the same visual quality. Use PNG only for logos or graphics with flat colours and sharp edges, and only when the site has no size limit, since PNG can't be steered to a size.

Check before you upload

If you already have a file, open Check a file: it reads the real format, size in KB and bytes, and pixels, and marks each against your rules. For photos with strict official rules, such as visa or passport photos, see the photo size rules pages, which say what each authority allows you to change.