A quick Google and I find that this has been a bug since 2004! This is such a simple fix. Why hasn't this been done???
Monday, October 3, 2011
Old graphicx Bug
I just ran into a bug using the LaTeX package graphicx. I tried to include a graphic with a file name of the form "name.txt.png" and the file really is a PNG file. However, graphicx said ".txt.png" is an unknown graphics extension. *Sigh*...thanks for the hot tip.