def IsImageFile(ext):
    """IsImageFile(ext) -> bool
    
    Determines if the given extension corresponds to an image file (jpg, bmp,
    or png).
    
    arguments:
        ext
            string corresponding to extension to check.
    
    returns:
        bool corresponding to whether it is an image file.
    
    """
    return (ext == "jpg") or (ext == "bmp") or (ext == "png")