A friend sent the attached logo for her restaurant to play with. Easy enough. Drag the PNG into the GFUI, then add a circle to cut it out.
Works great! But then I wanted to combine the cut with the bitmap so I could replicate the pattern in the GFUI easily at different sizes.
Dropping the image into InkScape and adding a circle was straightforward. However, the SVG imported from InkScape into the GFUI totally mucked up the bitmap. Lots of aliases and weird blocky effects.
Doing the same in Boxy SVG (A random SVG editor on OS X from the App Store-- it isn’t that great, but it isn’t awful either) works fine.
So, bottom line, be aware that InkScape + Bitmaps can end poorly.