It really depends on the way you want to fill the buffer with image data. If blitz will fill the buffer (read the data from somewhere, eg. using RTLMemoryMove with a Pointer given by the DLL) then it's pretty simple, all you need to do is writing them to the image, as muk suggested.
If the DLL will fill the buffer using a pointer sent by Blitz, you need to send a banks physical adress to the dll. you may send the bank handle to the DLL, as usual, but there's something faster that will let the DLL draw directly to a blitz image. See here:
http://www.blitzbasic.com/codearcs/codearcs.php?code=1518
If the DLL will fill the buffer using a pointer sent by Blitz, you need to send a banks physical adress to the dll. you may send the bank handle to the DLL, as usual, but there's something faster that will let the DLL draw directly to a blitz image. See here:
http://www.blitzbasic.com/codearcs/codearcs.php?code=1518