Increase PNG File Size Online — No Software to Install
Increase a PNG file to an exact size online, free, with nothing to install. The tool runs in your browser tab and pads the file with invisible data, so the image looks identical and your file never leaves your device.
Increase PNG file size
Runs entirely in this browser tab. Your file is never uploaded.
Drag a PNG file here, or
Nothing is uploaded when you pick a file.
How it works
- 1
Choose your PNG file
Drag a file onto the tool above or click to browse. It accepts .png files, and the file is read directly by your browser rather than sent anywhere.
- 2
Set your target size
Pick a preset from the dropdown or type an exact figure in KB or MB. The output will match that number byte for byte.
- 3
Choose how the size is added
The default pads the file with extra tEXt metadata chunks, an ancillary PNG block that decoders are required to ignore, so the image is untouched. Switch to "increase resolution" if you want more pixels as well as more bytes.
- 4
Download the result
Press the button and your browser saves the new file at exactly the size you asked for. Nothing was uploaded, so there is nothing stored anywhere for you to delete afterwards.
Why you might need this
Minimum file size rules turn up wherever documents are submitted in bulk: exam boards, immigration services, banking KYC forms and university applications. The rule is a proxy for "is this scan detailed enough to read", and modern compression is good enough that it regularly catches files that are entirely fine.
Because padding writes into extra tEXt metadata chunks, an ancillary PNG block that decoders are required to ignore, the file that comes out is structurally valid and visually identical. The validator is satisfied and the person reading your document sees exactly what you scanned.
Why PNG files behave differently
PNG is lossless, so it never throws detail away, but it is built for flat colour: screenshots, logos, diagrams and line art. A signature or a simple graphic can compress to a few kilobytes because a PNG can describe long runs of identical pixels almost for free. Photographs go the other way and stay large.
Padding a PNG adds ancillary tEXt chunks before the file’s IEND marker. Ancillary chunks are the part of the specification that says decoders may ignore what they do not recognise, so the IDAT pixel data is untouched and the image is identical.
Frequently asked questions
Will this reduce my image’s quality?
It cannot. Quality is only ever lost when a file is decoded and re-compressed, and this tool does neither — it writes extra tEXt metadata chunks, an ancillary PNG block that decoders are required to ignore and leaves the compressed image data exactly as it found them. Open the original and the result side by side and they are indistinguishable, because they are.
Is my file uploaded to a server?
Never. This site has no route that accepts a visitor file at all. Everything happens inside the browser tab you are reading this in, which is why it costs nothing to run and why a passport scan or bank statement is as safe here as it is in your own file manager.
What file formats are supported?
This page is set up for PNG images. The tool also handles PDFs and the other image format — drop any supported file in and it will detect the type from the file itself rather than the extension.
Why would I need to increase file size instead of decrease it?
Minimum size rules exist because file size is the cheapest available proxy for "is this scan readable". A form cannot easily judge legibility, so it judges bytes. Modern compression is good enough that a perfectly clear document lands under the threshold, and then the only thing wrong with it is the number.
Is this free to use?
Yes — free, with no account, no watermark, no email address and no limit on how many files you run through it. Because the work happens on your own device rather than on a server, there are no processing costs to pass on.