Steps for a 20 KB signature or photo
20 KB is the tightest limit most people meet, usually for a signature, a small ID photo or a thumbnail. At this size every byte counts, so preparation matters more than the compressor itself. This guide shows what to do before you press Compress and what results to expect.
- For a signature, sign in dark ink on plain white paper and photograph it in even daylight, without shadows. Clean white paper costs almost nothing to store; grey, shadowed paper costs a lot.
- Drop the photo or scan onto this page. The target is already 20 KB.
- Press Edit and crop tightly around the signature or face. Leave only a small border. This is the most important step at 20 KB.
- Keep the format on JPG. Forms that ask for 20 KB almost always expect a JPEG, and a photo saved as PNG will rarely fit.
- Press Compress and check the result card for the final size, quality and scale.
- Open the before and after slider, zoom in, and make sure every stroke or facial feature is still clear. Then download the file, or the whole batch as a ZIP.
Worked examples
These are typical outcomes for illustration. Your own results depend on lighting, background and detail.
A 4.2 MB phone photo of 4032 × 3024 pixels, compressed without cropping, usually ends up around 550 × 410 pixels at a quality near 50 percent, just under 20 KB. That is fine as a thumbnail, but a face in the middle of a wide shot is now only a hundred or so pixels across.
The same camera used for a signature tells a different story. Cropped to a strip of about 1,400 × 500 pixels around the ink, most of the frame is plain white. The compressor can usually keep the strip at or near that cropped size and simply lower quality until it fits, so strokes stay sharp. If the cropped signature is small enough to fit at top quality, it comes in under 20 KB with room to spare.
How much image fits in 20 KB
The type of image decides how many pixels survive. Plain areas are cheap, while texture and small text are expensive.
| Source image | Typical width at 20 KB | Verdict |
|---|---|---|
| Phone photo of a busy scene | About 500–600 px | Fine as a thumbnail; small details are gone. |
| Portrait against a plain wall, cropped | About 600–750 px | Good enough for most ID-style uploads. |
| Screenshot, 1920 × 1080 | About 800–950 px | Large text readable; small interface text is not. |
| Full A4 page of text | About 500–600 px | Not readable. Crop to one paragraph or use a bigger limit. |
| Tightly cropped signature on white | At or near the cropped size | Sharp; this is what 20 KB suits best. |
Limits at or around 20 KB
Here are the entries in our specification list where 20 KB is the ceiling or the floor. Note the last two rows: for those photos, 20 KB is the minimum, not the maximum.
| Upload | Size limit | Dimensions | Format |
|---|---|---|---|
| IBPS signature | 10–20 KB | 140 × 60 px | JPEG |
| PAN card photo (Protean / UTIITSL) | Up to 20 KB | 3.5 × 2.5 cm | JPEG |
| PAN card signature | Up to 10 KB | 2 × 4.5 cm | JPEG |
| SSC photo (CGL, CHSL, GD, MTS) | 20–50 KB | 3.5 × 4.5 cm | JPEG |
| IBPS photo (PO, Clerk, SO, RRB) | 20–50 KB | 200 × 230 px | JPEG |
A 20 KB target lands just under 20 KB, which is below the minimum for the SSC and IBPS photos. For those, use a target between the two limits, such as 40 KB, so the file is safely inside the window. For the PAN signature, type 10 KB instead of 20.
Troubleshooting at 20 KB
- The compressor says it could not reach 20 KB. It will not shrink an image beyond a small fraction of its original size. This happens most often with PNG output, because a lossless photo has to become tiny to fit. Switch to JPG and crop first.
- The signature looks grey or blotchy. Paper texture and shadows are being stored as detail. Retake the photo in brighter, even light, or scan it, and crop away everything but the ink.
- The photo looks soft. At 20 KB a full-frame photo cannot keep many pixels. Crop to head and shoulders so those pixels go to the face, not the background.
- The form says the file is too big. This tool counts 1 KB as 1,024 bytes. If the form counts 1,000, a file just under 20 KB here can read as 20.4 KB there. Set 19 KB.
- Your signature is a transparent PNG. JPG fills transparent areas with the background colour, which is white by default, exactly what signature forms want.
- The source is a HEIC photo from an iPhone. It is decoded on your device and saved as a JPG, so you do not need to convert it first.
Why not use an upload-based compressor
Signatures and identity photos are the files you least want copied. Upload-based tools process them on a server you cannot see, and you have to take their word on deletion. Here the image is compressed by your browser and never sent anywhere.
For a single signature, either approach is quick. The difference grows with batches, such as a school or office collecting photos for many people: up to 50 files run together on the free plan, 500 with Pro, with no upload time. Pro also lets the installed app work offline, which helps where the connection is unreliable.