For my wiki, I had a .png file for the favicon. I converted it into .ico. Then I uploaded the favicon and I got this error:

"File extension ".ico" does not match the detected MIME type of the file (image/x-bmp)."

Oh and just so you know, I used Pixillion Image Converter by NCH Software.

I can't upload the image AT ALL (it says: "File type verification error!"), but here is the .png file before conversion: DiamondOre incase you could upload it for me.