Your file was stopped by a format or size check, not by a broken uploader. The file picker offers more formats than the uploader accepts, so a file you were allowed to choose can still be refused a second later. SVG is the clearest case: you can pick it, and it will never upload.
Three separate limits apply, depending on what you are adding.
- Images in the project gallery: JPEG, PNG, GIF, WebP, BMP and TIFF, up to 20 MB each.
- The project cover image: JPEG, PNG or WebP only, up to 10 MB.
- Video: MP4 only, up to 2 GB and 30 minutes. See Video uploads.
SVG is offered by the picker and refused by the server
The gallery picker lists SVG, and the error you get if you pick something else even names SVG as allowed. It is not. An SVG file can carry JavaScript inside it, so the server blocks the extension outright and returns:
File type ".svg" is not allowed for security reasons
Export the artwork as PNG at the size you want it displayed. There is no setting that turns SVG on.
The cover picker offers four formats the cover will not take
The cover image picker offers GIF, SVG, BMP and TIFF alongside JPEG, PNG and WebP. Only JPEG, PNG and WebP are accepted. Choosing any of the other four gives:
Cover image must be JPEG, PNG, or WebP format
A cover over 10 MB gives "Cover image must be smaller than 10MB". A cover over 20 MB, or a file the browser does not read as an image, is dropped with no message at all: the picker closes and the cover does not change.
Reading the other refusals
- "... is not a valid image file. Only .JPG, .JPEG, .PNG, .GIF, .WEBP, .SVG, .BMP, .TIF, .TIFF files are allowed." The format is not on the gallery list. Ignore the SVG in that list.
- "... exceeds 20MB limit" The gallery file is over 20 MB.
- "File extension ".png" does not match actual content type ..." The file was renamed rather than converted. Re-export it properly.
- "File contains potentially malicious content" Script-like text was found inside an image file. Re-export from your original.
- "File too large. Maximum size is 100MB" The site-wide ceiling, reached on paths outside the gallery.
Converting to PNG or JPEG resolves nearly all of these. For size problems and iPhone HEIC photos, see Why does my upload keep failing?