As far as i can see, the problem is that the PyQt doesn't find correct 
image format plugins. You could try this: copy qt.conf from your 
PyQt/bin dir (my PyQt dir is located in C:/Python25/PyQt4) to your app 
dir and edit it so the Prefix key will be "." (without brackets). Now, 
create "plugins" folder in your app dir and copy there  "imageformats" 
dir  from your PyQt/plugins directory.  It should work.

PyQt image format plugins

Python