This page opens with Target size at 20 KB, the format set to JPG, and Maximum size at 400 × 400 pixels. That’s the scale of a scanned signature, a thumbnail or a small ID photo on an application form. Drop your image and the result is under 20,000 bytes.
20 KB is a small budget
A 20 KB file holds 160,000 bits. Spread over a full phone photo of 12 million pixels, that’s about one bit for every 75 pixels, which no format can turn into a usable picture. Over a 400 × 300 image it’s about 1.3 bits per pixel, which is where JPG starts to look clean. So the page limits the dimensions first and then searches for the highest JPG quality that fits. If quality 40 still doesn’t fit, it reduces the pixels further instead of producing a blocky image; the row tells you when that happened.
Signatures
A scanned signature is mostly white paper, which costs almost nothing, so it usually fits 20 KB at high quality with room to spare.
- Sign with a dark pen on plain white paper, and photograph it in daylight without a shadow across the page.
- Crop tightly around the signature in your phone’s photo editor. Empty paper makes the picture bigger without adding anything.
- Drop it here. If the form gives a size like 140 × 60 pixels or 4 × 2 cm, choose Custom width × height; at 200 DPI, 4 cm is 315 pixels.
If the form also has a minimum
Portals often accept a window, such as 10 to 20 KB. Because the tool stops at the best quality that fits and never pads files with empty data, a plain signature can come out under the minimum. Switch to the Quality tab and raise the slider, and check the size in the row again.
Before you upload
Zoom the compare view to 100%: letters and pen strokes should have clean edges. A gray, blotchy background means the scan was too dark, and brightening it before compressing also makes the file smaller.
The settings on this page
| Mode | Target size: under 20 KB (20,000 bytes) |
|---|---|
| Format | JPG |
| Maximum size | 400 × 400 px |
| Metadata | Removed (EXIF, GPS location) |
Every setting can be changed in the tool above; the page only chooses where it starts.