How to Compress a JPG Under 100KB

What makes a JPG big

A JPG's size grows with its pixel count and its quality setting. A 12-megapixel phone photo at high quality is 3 to 5 MB. Halving the width and height cuts the pixel count to a quarter, and dropping quality from 95% to 70% often halves the file again.

Quality or size first?

Lower quality first, down to about 60 to 70%. Below that, faces show blocky artefacts, and it is better to reduce the dimensions instead. For a portrait photo, 600 × 800 px at 70 to 80% quality fits comfortably under 100 KB.

Avoid rejected uploads

Aim a little under the limit (95 KB for a 100 KB rule), keep the JPG extension, and check any minimum size, pixel dimension or background rule in the form instructions.

• Crop away empty background before compressing: less area, fewer bytes.
• Compress the original photo each time, not a file that was already compressed.
• Keep the photo upright; some portals reject rotated EXIF images.

Why compress in the browser

ID photos and signed documents are personal data. A browser-based compressor keeps the file on your device, so there is no copy on someone else's server.