All the files are .BMP except the card frames are .PNG
Magic.exe requires to load some .PIC and some .BMP (Please refer to my screen shot at the link below. It will show you what files are needed for magic.exe)
Any of the files that need to be .PIC I just renamed the file extension from .BMP to .PIC (They are still .BMP files though) Just change the extension back to open in a image program. (I use Photoshop)
Unless you play Shandalar, I would clean the folders so they only have the files from my screenshot. Shandalar ONLY loads .PIC format, so it won't load any of the .BMP files and you will get a black square. Same with Magic.exe, if it is looking for a specific file and can not find it, it will either not start or load nothing and you get the black square.
If you have duplicate files (for example winbk_manapool.bmp & winbk_manapool.pic) it may load the incorrect one. (Stassy's screenshot above has an old manapool graphic, Unless he chose to use that one) Only some files it seems it can load either format.
My screenshot of required files
download/file.php?id=6466&mode=view