Compress Image to 100KB

What 100 KB is usually for

A 100 KB limit is common on job portals, university and certificate uploads, and web contact forms, and it is a sensible size for images you attach to email. It is roomy compared with the 20 KB and 50 KB caps used for signatures and ID photos, which changes the priority: at 100 KB you can usually keep a large, readable image, so the question is how to spend the bytes, not how to survive on very few.

Photographed documents: keep the text readable

Text is the hardest thing to compress well. JPEG stores images in 8 × 8 pixel blocks and treats sharp black-on-white edges as expensive detail, so letters are the first thing to blur or ring when quality drops. To keep a certificate or letter readable at 100 KB:

• Crop out the desk and everything around the page with the image cropper. Background clutter is pure waste.
• Shoot in even light. Shadows across the page turn into gradients the encoder must describe.
• Let it resize to around 1200 to 1600 pixels tall, if the portal allows. That is plenty for crisp text, and it lets the compressor keep a high quality.

Photos and screenshots

For an ordinary photo, 100 KB at 800 to 1000 pixels on the long side looks clean on any screen. Screenshots behave differently: they have large flat areas and sharp UI text, which JPEG handles poorly. For a screenshot, try WebP output first; it keeps edges cleaner at the same size. If the destination only accepts JPG, a slightly smaller maximum dimension usually looks better than a lower quality.

Exact bytes, and when to use a PDF instead

The compressor targets 100,000 bytes, so the file passes forms that count a kilobyte as either 1,000 or 1,024 bytes, and the result shows the exact count. If you need several pages in one upload, a PDF is usually the better container: build it with JPG to PDF and shrink it with the PDF compressor. For tighter limits, see the 50 KB compressor for ID photos, or the main compressor for any size you choose.