Capture it cleanly
Sign in dark ink on plain white paper and photograph or scan it in even light. A clean, high-contrast source compresses far smaller than a shadowy phone snap.
Then
- Crop tightly around the signature with a little white margin.
- Resize to the form's dimensions (often around 140 x 60 pixels).
- Compress to JPG and check you are under 20 KB.
Common reasons a signature is rejected
- Signed with a light ballpoint or pencil, so it fades after compression - use a black or dark blue gel pen.
- Lined, coloured or textured paper showing in the background.
- Too much empty space around the signature, so it appears tiny on the form.
- Photographed at an angle, making the signature look stretched.
Size and format checklist
Before uploading, confirm the file is JPG/JPEG, within the pixel dimensions the form gives (often around 140 x 60 px, but follow your form), and under the KB limit. Keep the original photo too, in case another form asks for a different size.