Signature for an Online Form: Get It to 10-20 KB

Many online applications ask for a scanned signature as a small JPEG, with a size range in KB. The Staff Selection Commission's notice for the Combined Graduate Level Examination, 2026 (published 21 May 2026) says: "The scanned signature in JPEG/JPG format (10 to 20 KB)." A phone photo of a signature is often a few MB, and the form rejects it with a message that doesn't say why.

This post turns a signature on paper into a file that fits, using free tools that run in your browser. The same steps work for a passport photo, with a different size.

What the notice actually asks for

Read the notice for your own form, because requirements change by exam and by year. In the SSC CGL 2026 notice:

• Format and size: JPEG/JPG, 10 to 20 KB.
• Shape: the notice gives centimetres, not pixels. One paragraph says the signature should be "about 6.0 cm (width) x 2.0 cm (height)", and another says "about 4.0 cm (Width) x 2.0 cm (Height)". Both say "about", so the file size is the firm part.
• Quality: applications with a blurred signature "will be rejected summarily".
• Photograph: the notice has candidates capture a live photo on the application page, so there is no photo file to prepare for that step.

Other forms may ask for a photo upload with their own KB range, and some give pixel sizes. The steps below are the same; only the numbers change. The upload page of your form is the final word.

Step 1: Make a clean source image

You need a picture of the signature on a plain background. Two ways:

• On paper. Sign with a dark pen on plain white paper and photograph it in even light, without a shadow across the page.
• On screen. Draw it in the Signature maker, which downloads a PNG with a transparent background. A JPEG cannot hold transparency, so open PNG to JPG next and keep the white fill it offers for the see-through areas. The signature then sits on a white square.

Step 2: Crop close to the ink

Open Crop image, drag the box tight around the signature, with a small even margin, and download. A signature is mostly paper, and cropping removes pixels that carry no ink. A tight crop also means the signature fills the picture, so it does not look "miniature", which the notice also warns about.

For the shape, 6.0 x 2.0 cm is 3:1 and 4.0 x 2.0 cm is 2:1. If your form gives a shape, crop to it.

Step 3: Set the size in pixels, if the form needs it

If the form states a width and height in pixels, set them in Resize image using exact pixels. If it gives only centimetres, as the SSC notice does, a width of a few hundred pixels at the right shape is a sensible start. A phone photo is much larger than that, and a smaller picture needs fewer bytes to look clear.

Resize does not enlarge a picture past its original size unless you tick "Allow enlarging past the original", and an enlarged picture looks softer, so work from a source that is already big enough.

Step 4: Compress to the KB range

Open Compress image and choose the File size mode. Type the upper limit as the target (20 for this notice), or start from the preset page for 20 KB or 50 KB. Set the output format to JPG.

The tool searches for the highest quality that still fits under the target, and reduces width and height only if quality alone is not enough. Check the size shown under the preview and drag the divider over the ink to see that the strokes are still clean.

Count KB the way the form does

The tool counts 1 KB as 1,024 bytes, so 20 KB is up to 20,480 bytes. A form that counts 1,000 bytes to a KB can reject a file that sits just under 20 KB here. Type 19 as the target and compress again.

If the file comes out below the minimum

A signature on plain paper compresses very well, so the result can land under 10 KB, and a range like 10 to 20 KB has a lower end too. The tool keeps the best quality that fits under your cap, so a file this small means the picture itself is small or plain. Go back to step 3 and make the picture larger in pixels (tick "Allow enlarging past the original" if needed), then compress again and check the size. A larger picture usually gives a larger file.

Step 5: Check before you upload

• The file is a JPG, not a PNG renamed.
• The size under the preview is inside the range your form states.
• The signature is readable when you open the file at full size.
• It looks like the signature you use on your other documents.

The same steps for a photo

For a passport-size photo, crop to the head and shoulders, resize if the form gives pixels, and compress to the form's limit. Use Compress to 20 KB or Compress to 50 KB for the two limits that forms commonly use, and type another number in the custom box for anything else. A face on a plain wall compresses better than a busy background, so retake the photo against a plain wall if the result looks blocky.

Your signature stays on your device

The signature maker, crop, resize and compress tools all run in your browser. The image is read from your device and saved back to it, and the file is not uploaded. The page itself and its analytics still load from the internet.

Frequently asked questions

How do I reduce a signature image to 20 KB?

Crop it close to the ink, resize it to a few hundred pixels wide, and compress it with the target size set to 20 KB and the output set to JPG. Check the size under the preview before you download.

My signature file is smaller than the 10 KB minimum. What do I do?

Make the picture larger in pixels with Resize image, then compress it again to the same cap. A larger picture usually produces a larger file. The compress tool keeps the best quality that fits under the cap, so it won't pad a small picture to the minimum on its own.

Why does a form reject a file that is under the limit?

Some forms count 1 KB as 1,000 bytes, and the compress tool counts 1,024. Aim a KB or two lower. Some forms also check the format, so make sure the file is a real JPG.

Can I use a photo of my signature taken on my phone?

Yes. Sign on white paper with a dark pen, photograph it in even light, then crop, resize and compress it as above. The Signature maker also accepts a photo of a signature and makes the paper background transparent.

What size should the signature be in pixels?

It depends on the form. The SSC CGL 2026 notice gives centimetres only, so no pixel size is fixed there. When a form gives pixels, use exactly those in Resize image.

Is my signature uploaded to your servers?

No. The tools process the image in your browser and do not upload it.

Sources

• Notice: Combined Graduate Level Examination, 2026, Staff Selection Commission, uploaded 21 May 2026 (scanned signature: JPEG/JPG, 10 to 20 KB; photo captured live on the application page).