Board Thread:General Discussion/@comment-27959912-20170203140309/@comment-1038387-20170203181622

The statement is fairly straightforward. "The name of the file you are uploading begins with "IMG", which is a non-descriptive name typically assigned automatically by digital cameras. Please choose a more descriptive name for your file."

The wiki in question has a spam filter set up so people can't upload images with those letters at the beginning in the name. "IMG" is common, as is "DSC" and "tumblr". Wikis with an image policy take preemptive steps to clear out badly named images. You say you can upload it if you change the name... that's the entire point of this. Check the local image or naming policy to see what's an acceptable name.