My logo or banner was refused

The image has to be a PNG, JPEG or WebP, and within the size the page states beside the field.

A file renamed to end in .png is still whatever it was. The check reads the file itself rather than its name, so renaming will not get it through.

If the file is genuinely one of those formats and the upload still fails, write to support with the file and we will look at it rather than leave you guessing.

If this did not answer it: support inside your account is under development, and until it opens, this says what does reach a person.