If I load an 8-bit (or less) picture (gif/png) using datatypes, while specifying "PDTA_SCREEN,myscreen, PDTA_USEFRIENDBITMAP,FALSE", and then extract the bitmap using PDTA_DESTBITMAP, then the resulting bitmap seems to be blank (at least after being blitted to the screen). I don't get this problem on AmigaOS4.1.
Note that if I specify PDTA_USEFRIENDBITMAP,TRUE then it loads fine. Alternatively, if I do not specify a screen (and set PDTA_REMAP,FALSE) then it also loads OK (except the colours look wrong as you would expect).
I could probably devise an example using PortablE, if requested.
I forgot to mention that I am using "PDTA_DESTMODE,PMODE_V43", since you can't easily know in advance the picture's depth. It kind-of works (looks a bit ugly) when not using V43 mode.