Is this a bad indicator that uploaded PNG images show as broken links?
Does this site happen to be running the image optimization tool and Xenforo 2.3.5?
Seems that 2.3.5 has broken many an add-on with their quick release and inability of developers to test it for any length of time and their normal " you aren't told shit until it is released and the broken things show up" attitude.
And if you can't tell... I'm beyond exasperated with the "new" Xenforo developer attitude. It sucks salty ones.