Compress Image to 500 KB

Compressing scanned documents and ID cards

Many upload forms that accept 500 KB are asking for documents — a proof of address, a certificate, a receipt, the front of an ID card — rather than portraits. Documents behave differently from photos: large areas of white paper cost almost nothing, while the edges of letters are exactly where JPG artefacts show up first.

Scan resolution decides most of the file size. For a document that only needs to be read on screen, 150–200 DPI is plenty; 300 DPI is the print-shop standard and makes files several times larger for detail no reviewer will look at.

Getting a sharp document under 500 KB

• Crop away the scanner lid or tabletop around the page — dark borders are expensive and look careless.
• Use even, shadow-free light when photographing a document with a phone; gradients across the page cost bytes and hurt legibility.
• If the page is text only, scan it in grayscale: it's smaller than colour and just as readable.
• A 200 DPI A4 scan normally fits in 500 KB with text still crisp. A 300 DPI colour scan often doesn't — resize it to roughly 1650 pixels wide first.

500 KB for photos

For regular photos, 500 KB is a generous budget up to about 2000 pixels on the long side — enough for classified ads, property listings, club websites and most forms that ask for a high-quality image. A full-resolution 12-megapixel phone photo usually needs resizing to get there without visible loss.