Loads an image from an ALLEGRO_FILE(3alleg5) stream into a new ALLEGRO_BITMAP(3alleg5). The file type is
determined by al_identify_bitmap_f(3alleg5). If identification is not possible, the passed `ident'
parameter, which is a file name extension including the leading dot, is used as a fallback, if it is not
NULL.
The flags parameter is the same as for al_load_bitmap_flags(3alleg5).
Returns NULL on error. The file remains open afterwards.
Note: the core Allegro library does not support any image file formats by default. You must use
the allegro_image addon, or register your own format handler.