How do I reduce a photo to 50 KB (or 20 KB) for an online form?

Make a photo under 50 KB (or any size)

1. Drop the photo at the top of this page: JPG, JPEG, PNG, HEIC from an iPhone, WebP and more. It opens at once, with its size in pixels and KB.
2. If the form gives a size in pixels (such as 200 × 230), crop the photo to that shape with Crop, then type the width under Width (pixels).
3. Under Download as, keep JPG, choose File size instead of Quality, and type the form’s limit in At most (KB), for example 50.
4. The expected size is shown under the photo. Click Download JPG.

Tip: Everything runs in your browser: photos up to 200 MB are never uploaded, which matters for ID photos and signatures. The converters work too: open Options and type the limit in Largest file size (KB).

How it gets under the limit

ConvertKitty tries qualities from high to low and keeps the best one that fits under your limit, so the photo loses as little as possible. A full-size phone photo usually can’t reach 50 KB by quality alone, so it is then made smaller in pixels, a step at a time, until it fits; a note says what size it became.

For the sharpest result at a small size, give the pixel size yourself: a photo 600 pixels wide at 20 KB looks much better than a full-size one squeezed to 20 KB.

We tested it: two iPhone photos

We made two real iPhone photos of about 3 MB fit common form limits, with the same engine your browser runs. Every result came in just under the limit. Without a pixel size, the photo was made smaller automatically; with one, the conversion was faster and the size exactly as asked.

Tip: Tested on 8 November 2026 with a 12-megapixel iPhone photo on a laptop; a phone takes longer, and smaller photos are quicker.

Signatures under 10 or 20 KB

• Sign in black or dark blue ink on plain white paper, and photograph or scan it in good light.
• Drop it at the top of this page and crop it close around the signature with Crop.
• Type the form’s pixel width, choose File size and the KB limit, and download the JPG. A signature has little detail, so it fits small limits easily.

When the form says “file type not allowed”

KB, pixels and centimetres: what forms mean

KB (kilobytes) is the size of the file. Pixels (such as 200 × 230) is the size of the picture. Centimetres (such as 3.5 × 4.5 cm) is the printed size; for a screen form it is usually the pixel size the form lists that matters. Read the form’s instructions: most give both a KB range and a pixel size. Some also ask for a minimum (for example “between 10 and 50 KB”); if the result is too small, raise the limit or the pixel size a little.