Three ways to make an image file bigger
When a form says “minimum 10 KB” and your file is 4 KB, there are only three things anyone can do to it. We tried all three on the same file: a scanned signature at 140×60 pixels, the “preferred” size in the 2026 IBPS bank exam notice, which also asks for a file between 10 and 20 KB.
| Method | Result | Problem |
|---|---|---|
| Save at a higher quality | 3.1 KB at quality 0.92, 5.8 KB at the maximum (1.0) | Still half the minimum. There is nothing more to save. |
| Make it bigger in pixels | Reaches 10–20 KB somewhere between 280 and 420 pixels wide | No longer 140×60, which the same form asks for |
| Add padding (this tool) | Exactly 10,240, 15,360 or 20,480 bytes | None: still 140×60, every pixel identical |
Raising the quality has a ceiling, and a small, mostly white image like a signature hits it early: white paper compresses to almost nothing however carefully it is saved. Enlarging the picture works for the file size but breaks a pixel rule, if the form has one. Padding is the only method that changes the file size and nothing else.
What the padding is
JPEG and PNG files can carry comment blocks: short notes that sit next to the image data and that every viewer skips. Cameras and editing programs write them all the time. This tool adds one, filled with blank space, until the file reaches the size you picked. In a JPEG it goes right after the header, so the camera information and the rotation flag stay where they are; in a PNG it goes just before the end marker.
We checked the results with two independent decoders, Chrome’s and Pillow’s: the padded signature, a rotated phone photo and a transparent PNG all decoded to exactly the same pixels as the originals, transparency included. The phone photo kept its rotation flag. Each file landed on the exact number of bytes asked for, from 10 KB up to 1 MB.
Why sizes are counted as 1,024 bytes
“100 KB” means 100,000 bytes to some websites and 102,400 bytes to others; the form rarely says which. For a minimum, the safe choice is the larger number, because a file of 102,400 bytes is at least 100 KB under both definitions, while one of 100,000 bytes fails a form that counts in 1,024s. So each preset here produces 1,024 bytes per KB. Our guide on why a 500 KB file fails a 500 KB limit explains where the two kilobytes come from.
If the form gives a range
Many forms set both ends: “signature 10–20 KB”, “photo 20–50 KB”. First make sure the file is under the maximum; if it is too big, shrink it with compress image to 20 KB or 50 KB. Then, if it ended up under the minimum, bring it back up here. Aim for the middle of the range, 15 KB for 10–20, so a different way of counting at either end cannot catch you out.
What this tool will not do
- It will not improve the picture. A blurry scan stays blurry. If the form rejects the image for being unreadable, rescan it at a higher resolution.
- It will not change the pixel size. If you need a bigger picture, not just a bigger file, use Resize Image.
- It will not shrink anything. A file that is already over the size you pick is left exactly as it is.
Nothing is uploaded
Signatures and ID photos are exactly the kind of file you should not hand to a random website. This tool reads and pads the file in your browser; it never leaves your device, and there is no account or watermark.
How this was measured. On 1 October 2026, in Chrome. The signature is a 300 dpi scan (708×236) scaled to 140×60, saved with Chrome’s own JPEG encoder. The pixel range for enlarging comes from our 20 KB page’s measurement of the same notice. Padded files were compared pixel by pixel with the originals in Chrome (canvas) and Pillow; the rotated photo’s EXIF orientation was read back with Pillow.