Well I spent a while working on this in PyQt4 and got strange results.

When selecting the "BMP" option, the filename automatically got ".bmp" added to the end of it. When selecting the PNG or JPG I got nothing. Sometimes random special characters would show up in the drop down list.

In all cases.. the selectedFilter never properly updated, and getSaveFileNameAndFilter() would never return anything in the filter index.

There is definitely an issue here. Reading online I've seen other people have similar issues but everyone else just says "Works fine for me."

Using the DontUseNativeDialog both worked fine, as you witnessed.

Odd.