I installed 3.3.4b1 over 3.3.2, and all buttons images are missing from the main menu and toolbars. This may be because I installed over 3.3.2 but did not see any particular advisory to the contrary. I have no more detail than that as I uninstalled it with the quickness and put 3.3.2 back, but I can at least say that reinstalling 3.3.2 got them back, for 3.3.2.
#3.4b1, sorry.
Already reported as Bug 36263 - No icons in user interface *** This bug has been marked as a duplicate of bug 36263 ***