A quick note on point 1. In this instance, there is no such thing as dpi. DPI is a measurement used for print. It is meaningless for web graphics. The actual preferred spec is 512 pixels by 512 pixels. Even thought they will appear very small on screen, this is the optimal size for reduction at the final display sizes. Here are the specs from the Help Center: The ideal size for a token marker is 512 x 512, and marketplace creators making their own sets should use these dimensions. When they get applied to your token, they'll be resized to 48 x 48 or smaller, depending on the token size and scaling of the markers, but the larger size future-proofs your tokens for a future feature. Token markers can be .gif, .png, or .jpeg/.jpg formats. Animated token markers are not supported at this time; if you upload an animated gif, only one frame will be uploaded and displayed. My recommendation, unless you are creating square markers would be to use a format which natively supports transparency, such as png. And save it as 512x512 pixels. Given the fact that the Roll20 software wants you to rename an image, my best guess would be that Xenobunny is likely on the right track with point 3. I don't know if the profanity filter affects personal uploads, but it might for marketplace images. Another possibility is the inclusion of characters that are "illegal" for certain file naming conventions: starting a name with a period, including a slash in a name, or some upper register or accented characters, that sort of thing.