By CutImage · Updated
An upload form may accept an image only below a fixed number of bytes. That limit is separate from its required width and height. To meet both, adjust composition and dimensions first, then tune the encoding, checking the actual downloaded file after each meaningful change.
1. Write down all three requirements
Check the allowed file type, the pixel dimensions and the byte limit. For example, a form might ask for a JPEG under 200 KB and at least 800 pixels wide. Changing the extension from .png to .jpg does not convert a file or reduce its size.
CutImage labels 1,024 bytes as 1 KB. Another service may use 1,000 bytes. For a 200,000-byte limit, target about 190 KB in this tool rather than relying on a rounded “200 KB” display. Read the receiving service’s exact instructions when available.
2. Remove unnecessary pixels
Suppose the source is 4,000 × 3,000 and the form needs 800 × 600. Resizing reduces the pixel count from 12 million to 480,000, a factor of 25. That does not promise a 25-fold reduction in bytes; the encoder and image detail also matter. It is a useful first step because the extra pixels are not required.
Use Crop first if a different shape is needed, then Resize with the aspect ratio locked. Do not make text so small that the information becomes unusable.
3. Select a format and try a target
Open the resized result in Compress. Choose JPEG for an opaque photo or WebP if the destination accepts it. Enter a target such as 190 KB and select Compress All. The target search changes quality within the browser encoder; it cannot guarantee that any arbitrary image fits at its current dimensions.
If the lowest available quality still exceeds the limit, the tool reports that the target cannot be met. Reduce the dimensions if the form allows it, or simplify the image before trying again. PNG ignores the lossy quality slider, so a PNG target cannot be reached by lowering that control.
4. Inspect the file you will actually submit
- Open the downloaded file and check its true byte size.
- Confirm the dimensions still meet the minimum requirement.
- Inspect faces, text, QR codes and thin line drawings.
- Check for an unwanted white background if you switched from transparency to JPEG.
If a file becomes smaller but its information is unreadable, it has failed the task. Return to the original and try a different balance of pixels and quality. Avoid repeatedly recompressing a previously damaged JPEG.
Why did the output get larger?
An image may already be efficiently compressed. Converting a photo from JPEG to PNG or exporting a heavily optimized WebP again can increase bytes. Do not replace the original merely because an export completed. Compare both files and keep the one that meets the destination’s requirements.
For a format-by-format decision, see JPEG, PNG or WebP. Your selected files stay in your browser during the CutImage workflow.