int ok = hw_IsImage(STRPTR file, int *width, int *height, int *alpha);
hw_IsImage() will return its dimensions in pixels as well as a boolean value that
indicates whether or not the image uses alpha channel transparency.
hw_IsImage() is the preferred way of checking if a file is in a supported image format
as it just scans the file header and is thus very fast.
Use hw_LoadImage() to load the image. See hw_LoadImage for details.
int that receives the image's width in pixels on successint that receives the image's height in pixels on successint that receives the image's alpha channel setting on success
(either True or False)True if the file was recognized as an image file, False otherwise