Is the limit in MB or in pixels?
Read the error or the help text next to the upload button. “Maximum file size: 5 MB” is a file size limit, measured in bytes. “At most 4,000 × 4,000 px” or “exceeds 25 megapixels” is a dimension limit, measured in pixels. Some platforms have both: Shopify, for example, takes product images under 20 MB and up to 5,000 × 5,000 px (25 megapixels), and Google Docs takes images under 50 MB and up to 25 megapixels. The upload limits by platform table lists the common ones.
Which fix matches my error?
| The error says | Limit type | Fix |
|---|---|---|
| “File too large”, “exceeds 2 MB”, “maximum upload size” | File size | Compress with a target a little under the limit (1,900 KB for 2 MB) |
| “Dimensions too large”, “max 4,096 px”, “too many megapixels” | Pixels | Resize so the longest side is under the limit |
| “Image too small”, “minimum 54 KB”, “at least 1,000 px” | Minimum | Start from the original; use a higher target; never upscale |
| “Unsupported file type”, “invalid format” | Format | Save as JPG (HEIC, AVIF and TIFF are often refused) |
| Upload stalls or times out with no message | Usually file size | Compress to a few hundred KB and try again |
How do I fix a file size limit?
- Open the compressor at the right size: Image to 500 KB, Image to 1 MB, Image to 2 MB, or the compressor with Target size set to any number.
- Type a target a little under the site's limit, for example 950 KB for a 1 MB limit.
- Choose JPG as the output if the site may not accept other formats; JPG is the format almost every upload form takes.
- Drop the image and compress. The tool keeps the highest quality that fits and shrinks the dimensions only if quality alone is not enough.
- Download the file and upload it again.
How do I fix a pixel limit?
In the compressor, turn on Limit width and type the maximum width; the height follows proportionally and smaller images are never enlarged. Resize is off by default on the compress pages, so switch it on. For a portrait photo, the height is the long side: to keep a 3,024 × 4,032 photo under 2,000 px tall, set the width to 1,500. If the site states a megapixel limit, multiply width by height to check: 5,000 × 5,000 is exactly 25 megapixels.
What if the site rejects the format, not the size?
Two formats cause most of these errors. iPhone photos are HEIC by default, and many forms only take JPG or PNG. Images saved from websites are often WebP, because browsers download what the site served. In both cases, run the file through the compressor with JPG as the output (or PNG for a logo with transparency), and the form will accept it. HEIC files open in Safari; the other formats open in any browser.
How do I fix it on a phone?
- iPhone: open the compressor in Safari, which is the browser that can read HEIC photos, pick the photo from your library, compress, and download the result before uploading it. To stop getting HEIC files, choose Settings > Camera > Formats > Most Compatible. More options in reducing photo size on iPhone.
- Android: open the compressor in Chrome, pick the photo, compress and download; the file lands in Downloads, ready to upload. See reducing photo size on Android.
- Windows or Mac: drag the file into the compressor in any browser, then upload the downloaded copy.