How to Increase File Size in Photoshop (and a Faster Free Alternative)
In Photoshop, you increase a file’s size with Image → Image Size (raise the pixel dimensions or resolution) or by saving at a higher quality setting in File → Export → Save As. Both change the image data itself. If you only need the file to clear an upload form’s minimum size, the free tool below does it in seconds without Photoshop.
Increase JPG, PNG or PDF file size
Runs entirely in this browser tab. Your file is never uploaded.
Drag a JPG, PNG or PDF file here, or
Nothing is uploaded when you pick a file.
How it works
- 1
Choose your file
Drag a file onto the tool above or click to browse. It accepts JPG, PNG and PDF 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 metadata areas that the file format reserves for data decoders 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 a form would reject a file for being too small
The form is not judging your image — it is judging its byte count. That rule was written to stop people uploading unreadable 5KB scans, and it has no way of telling those apart from a clean scan that simply compressed well.
Rescanning at a higher DPI would also clear the threshold, and if your scan really is hard to read that is the better fix. If it is fine and only the number is wrong, padding it is the honest shortcut: the bytes go into metadata areas that the file format reserves for data decoders ignore, and the person who opens the file sees exactly what you scanned.
The Photoshop method, step by step
Open the file in Photoshop and choose Image → Image Size. Tick Resample, set the width or height higher, and pick "Preserve Details 2.0" from the resampling dropdown. A larger pixel count produces a larger file when you save.
Then use File → Export → Export As (or the older Save for Web) and raise the Quality slider toward 100 for JPG, or choose PNG-24 instead of PNG-8. Photoshop shows the estimated file size in the export dialog, so you can nudge the slider until the estimate lands near your target.
For PDFs, File → Save As → Photoshop PDF and choosing "High Quality Print" or "Press Quality" from the Adobe PDF Preset dropdown will produce a noticeably larger file than the "Smallest File Size" preset.
Why Photoshop cannot hit an exact number
Photoshop’s quality slider is an approximation. Compression is content-dependent, so quality 87 on one photo lands at 94KB and on another at 220KB. If a form demands "at least 100KB", you end up exporting repeatedly and checking the file in your file manager each time.
The tool on this page works the other way around: you type the exact number of kilobytes you need and it produces a file of exactly that size, on the first try, by padding the file with data that decoders ignore.
When Photoshop is still the right choice
If the real problem is that your image is too small or too soft — a logo you need at print resolution, a photo that will be enlarged on a poster — then you want genuine resampling, and Photoshop’s Preserve Details algorithm is better than a browser canvas. Use the "increase resolution" mode here for a quick result, and Photoshop when the output has to hold up at print size.
Frequently asked questions
Will this reduce my image’s quality?
No. The padding goes into metadata areas that the file format reserves for data decoders ignore, so the image data is never decoded or re-compressed. What comes out is pixel-for-pixel identical, just larger on disk.
Is my file uploaded to a server?
No, and you do not have to take that on trust. Load this page, disconnect from the internet, and use the tool — it still works, which it could not do if your file had to reach a server. Nothing is transmitted, so there is nothing stored and nothing to delete afterwards.
What file formats are supported?
JPG (including .jpeg), PNG and PDF. Each one is padded using the structure its own specification reserves for data readers can ignore, so the output is always a valid file of that type.
Why would I need to increase file size instead of decrease it?
Because some upload forms enforce a minimum as well as a maximum. The minimum is meant to reject scans too low-quality to read, but it catches efficiently compressed files too. When your file is legible and simply small, making it bigger is the only thing standing between you and a successful submission.
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.