Factorio Forums

FF 283 finally specifies the technical specification for the thumbnail.png file to be included as part of distribution package to be 144x144 bits in size.

Recommend changing the text on the mod upload page to include the expected size of the thumbnail.png file to something like:

Note: From 0.17 onwards, to set a thumbnail for your mod, please include a 144x144 thumbnail.png file in your mod ZIP archive.

Hiladdar

Now that 0.17 is out i tried including a thumbnail with my mod and it worked with a 360x360 file.