Compress signature for RRB 2026

The RRB official signature spec

The Railway Recruitment Boards wrote this rule once and reused it. These notices print it identically:

• RRB ALP CEN 01/2026 — Detailed Notification (pp. 17–18, §13.4–13.5, dated 14.05.2026)
• RRB NTPC CEN 06/2025 — Detailed Notification (p. 22, §14.5.1, dated 21.10.2025)
• RRB NTPC (Undergraduate) CEN 07/2025 — Detailed Notification (p. 23, §14.5.1, dated 28.10.2025)
• RRB Group D CEN 09/2025 — Detailed Notification (pp. 31–33, dated 31.01.2026)

The table above quotes the wording from the first of them. One file prepared to it works for whichever of these posts you are applying to.

The photo is taken on the form, not uploaded

Railway applications no longer accept a scanned passport photograph. The notice says: The application module is designed to capture a live photograph of the candidate The camera step happens inside the application. The instruction it gives about that picture is about you, not a file: non-white clothing, preferably dark colours. So leave the photo resizer alone and spend the effort on the signature.

Why this band is heavy, and what that means

Compare it with other recruiters. The Staff Selection Commission’s signature ceiling is 20 KB; the railway floor is 30 KB. A neat, tightly cropped signature compressed hard can easily come in under the railway minimum. The usual problem here is a file that is too small, not too big.

When that happens, do not pad the image with blank paper. Keep the crop and raise the quality instead, or keep more pixels. The tool reads the lower limit at 1,024 bytes per kilobyte, so it will not stop until the file is at least 30,720 bytes. It also keeps the file at or under 49,000 bytes, reading the ceiling at 1,000 bytes per kilobyte. A file between those passes either reading. For a general upload with only a ceiling near this band, compress an image to 40 KB shows what that size holds.

The 35 × 20 mm box and the 100 DPI trap

The notice asks for the signature inside a box 35 mm wide and 20 mm tall, scanned at no less than 100 DPI, and gives a pixel floor of 140 × 60. Do the arithmetic and the two minimums do not quite meet. A box that size scanned at exactly 100 DPI comes out about 138 × 79 px, and the width is short of the floor.

The fix is simple: scan above the minimum. At 200 DPI the same box is about 276 × 157 px, clear of the floor with room to spare. A phone photo held square to the page gives you far more than that. There is no pixel maximum in the notice, only the floor.

How the signature itself must look

Two of the rules in the table are about handwriting, not pixels: the ink and paper, and the style of the signature itself. Compression cannot rescue either. The style rule catches people who sign in neat separate capitals for official forms. Railway notices want your ordinary joined-up signature. If you have already scanned a block-letter version, sign again.

Once the sheet is signed, photograph or scan it and trim it to the box. If you want the crop exact before compressing, crop the scan first. Then drop it into the tool above.

Applying elsewhere too

Keep your source scan, because the next form will want something different. An SSC signature has to fit 10–20 KB, so this railway file is far too heavy for it. The government exams hub lists each exam page MiniPx has checked against the official notice.

Your signature is compressed inside your browser and is never uploaded to MiniPx. The exact output size is shown before you download it.