Image format for menu bitmap - compilation error

What is the image format for the bitmap attached to a menu item? When opening the icon selector in the object inspector for a menu item it appears to expect a bmp icon but compiling yields the following compile error:

Unsupported image class [ followed by control chars presumable thebml file itself ]


I assume what it wants is a png based icon?

I found out how to include images from the main main demo.