Silent failure on other image types than .png

[fryguybob]

(Imported from http://code.google.com/p/diagrams/issues/detail?id=41. Original issue from alea...@gmail.com on August 30, 2011, 02:39:41 PM UTC)

What steps will reproduce the problem?

1. compile "defaultMain (image "any.jpg")
2. ./main -o foo.pdf

• What is the expected output? What do you see instead?

Either an error message telling that .jpg filetype is unsupported or a foo.pdf that contains
image instead of blank

• What version of the product are you using? On what operating system?
  diagrams-cairo-0.3

[fryguybob]

(Imported. Original comment by byor...@gmail.com on August 30, 2011, 09:42:21 PM UTC)

Tue Aug 30 17:41:43 EDT 2011 Brent Yorgey byorgey@cis.upenn.edu

• Emit warning for embedded images of file type other than .png. Fixes Add lookupName function. #41.