Exam and bank forms want a scanned signature as a tiny JPG, typically 140 × 60 pixels and between 10 and 20 KB, on a white background. A photo of your signature straight from a phone is a thousand times too large and the wrong shape. Three short steps in your browser get it right.
1. Sign on paper, photograph it flat
- Use a black or dark blue pen on plain white paper. Sign at normal size inside a box you draw of roughly 7 × 3 cm, the same proportion as 140 × 60 pixels.
- Photograph it in daylight, straight from above, so the paper looks white and not grey. Fill the frame with the box.
- If the paper looks grey, tap the brightness up in your phone’s photo editor until the paper is white and the ink is still dark.
2. Crop and resize to the exact pixels
Open Resize image and drop the photo.
Choose Custom and type the width and height from the form, for example 140 and 60. Some forms ask for 140 × 60, others for 300 × 80 or “between 1 × 3.5 cm and 2 × 4.5 cm”; use the numbers on your form.
Keep the Cover fit and drag the picture so only the signature and a little white around it are inside the frame.
Export as JPG. At 140 × 60 pixels the file is a few KB.
3. Land between the minimum and the maximum
Most rejections here are for a file that is too small, not too large: a 140 × 60 JPG is often 4 or 5 KB and the form wants at least 10 KB. Fix it by exporting at a higher JPG quality in Resize image, or by using a slightly larger pixel size if the form allows a range. If the file is too large, run it through Compress image and pick Light.
Signing a PDF instead?
If the form itself is a PDF you have to sign and send back, you do not need a signature image at all. Sign PDF lets you draw, type or upload a signature and place it on the page, then saves the signed PDF, all inside your browser.
Questions, answered
- How do I make the signature file bigger than 10 KB?
- Export at a higher JPG quality or use the largest pixel size the form allows. A 140 × 60 JPG of a clean signature is often under 10 KB on its own, so the fix is more quality, not compression.
- Does the background have to be white?
- Nearly every form says so. Photograph the paper in good light and brighten it until it reads as white. Do not use Remove background here: a transparent PNG becomes a black box in many form previews.
- Is my signature uploaded anywhere?
- No. Resize image and Compress image run in your browser, so the photo of your signature never leaves your device.