How to make an image fit an upload size limit

Reduce the file size without changing dimensions

1. Open the image compressor and choose your image. JPG, PNG, and WebP inputs are supported, up to 20 MB and 40 megapixels. Keep the original file so you can return to it.
2. Choose “Fit a file size limit” and enter the maximum KB. Use 50, 100, 200, or 500 KB, or enter a whole-number limit from 10 to 20,000 KB.
3. Choose an accepted output format. JPEG turns transparent areas white. WebP can keep transparency, but the receiving site must accept it. This tool does not provide compressed PNG output.
4. Keep the original pixel size. In “Pixel size options,” leave maximum width blank and “Allow smaller dimensions if needed” unchecked. Then press “Compress to size limit.”
5. Check the bytes and the preview before downloading. “Within your file size limit” means the measured output fits. Look closely at small text and edges; fitting the limit does not guarantee readable details or acceptance by the receiving site.

What if it is still over the limit?

Some images cannot fit a very small limit while keeping the same dimensions within this tool’s quality range. Pocket Tools shows the over-limit result and disables its download instead of calling it a success.

If the destination allows smaller dimensions, select “Allow smaller dimensions and retry.” The tool will try smaller pixel sizes and show the resulting width and height. Check those against the destination’s minimum dimensions. If exact dimensions are required, keep resizing off and use a source image that meets the requirements.

For a website you manage, you may be able to choose a higher KB limit. For someone else’s form, follow its stated limit.

A measured example: same image, different limits

In a browser test on September 25, 2026, we used a deliberately detailed 1200 × 900 synthetic image. These are actual test outputs, not expected savings for every image.

Image detail, format, and browser affect the result. A flat illustration, a photograph, and a screenshot will not compress identically.

The file fits, but the upload is rejected

• Check the new file, not the original. Select the downloaded result when returning to the form. Verify its size in file properties; rounded KB labels can hide a small overage.
• Check format and dimensions again. A smaller WebP will not help a JPEG-only form. This tool does not validate a destination’s crop, aspect ratio, or content rules.
• Allow a little room below the stated limit. If the site rejects a file near the maximum and gives no exact byte count, try a slightly lower target, then check readability again.
• Use the original if it already meets all requirements. Recompressing a compact image can increase its size or reduce quality without helping.