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Byte budget · minimum size
Increase image size in KB
Some upload forms specify a range rather than a ceiling — "between 20 KB and 50 KB" is a common one — and reject a file for being too small just as readily as for being too large. There are two honest ways to make a file bigger, and this tool does both.
Result
The two methods, and when each is the right one
Padding the container
Both JPEG and PNG are container formats with slots for data a decoder is required to skip over. JPEG has comment segments; PNG has ancillary chunks. Padding mode fills those slots with inert filler until the file reaches your target. The compressed image data is copied across byte for byte, so the picture that comes out is pixel for pixel identical to the one that went in. Nothing is upscaled, nothing is blurred, no quality is lost, because no pixel is ever re-encoded.
This is the right method when a form has a minimum file size and you want your photo to keep looking exactly as it does now. It is a container trick, and it is worth knowing that a small number of strict validators reject files with unexpected segments. If a form refuses the padded file, switch to the other method.
Re-encoding larger
The alternative is to genuinely give the file more data to hold: raise the JPEG quality towards the top of its range, and if that is not enough, enlarge the pixel dimensions. The result is a legitimately larger file with no unusual structure in it, at the cost of a slightly softer image if upscaling was needed. Use this when the validator is fussy, or when the form checks minimum pixel dimensions too.
Steps
- Drop in the file that is being rejected for being too small.
- Enter the minimum size the form asks for. Add a kilobyte or two of margin.
- Start with padding. Check the result opens correctly in your photo viewer.
- If the form still refuses it, run it again with re-encode.
Common questions
Does padding change how my photo looks?
Not in any respect. The entropy-coded image data is untouched, so every pixel decodes to exactly the same value it did before. Only the file length changes. You can verify this by opening the before and after files side by side.
Can I increase file size without losing quality?
With padding, yes, in the strict sense that no quality is lost. What you cannot do is add detail that was never captured. If a form wants 200 KB and your source is a heavily compressed 8 KB thumbnail, no tool can recover the detail that the original compression threw away. Padding gets you a valid 200 KB file that looks exactly like an 8 KB thumbnail.
Which method should I use for a government exam form?
Try padding first, because it protects the image. Portals that only check
filesize accept it without complaint, and that is the overwhelming majority.
If you get an error mentioning an invalid or corrupt image, use re-encode instead.
Why is the file a few bytes over my target?
A padding segment has four bytes of header before its payload begins, so the smallest increment is five bytes. When the gap left to fill is smaller than that, the tool overshoots by up to three bytes rather than leaving you short of a minimum.
Is there a version of this for PDF files?
Yes, on the increase PDF size page. It works on the same principle, using an unreferenced object stream inside the PDF.
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