sub _is_wide {
        # widescreen 16:9 or 16:10
        my ($width, $height) = @_;
        return 1 if (($width / 16) * 9) == $height;
        return 1 if (($width / 16) * 10) == $height;
        return;                                     
}                                                   

sub _is_regular {
        # 4:3 (800x600) 5:4 (1280x1024)
        my ($width, $height) = @_;     
        return 1 if (($width / 4) * 3) == $height;
        return 1 if (($width / 5) * 4) == $height;
        return;                                   

}

sub img_size {
        my ($width, $height) = @_;
        return BM_SIZE_UNKNOWN    
                unless $width && $height;

        my $size = 0x0;

        if ($width <= 800 || $height <= 600) {
                $size = BM_SIZE_TINY;         
        }                                     
        elsif ($width <= 1024 || $height <= 768) {
                $size = BM_SIZE_SMALL;            
        }                                         
        elsif ($width <= 1280 || $height <= 1024) {
                $size = BM_SIZE_MEDIUM;            
        }                                          
        elsif ($width <= 1600 || $height <= 1200) {
                $size = BM_SIZE_LARGE;             
        }                                          
        elsif ($width > 1600 && $height >= 1200) { 
                $size = BM_SIZE_HUGE;              
        }                                          
        else { croak "Unable to classify w: $width h: $height"; }

        # Additional size attributes
        # See http://en.wikipedia.org/wiki/Computer_display_standard
        $size |= BM_SIZE_WIDE                                       
                if _is_wide($width, $height);                       
        # regular                                                   
        $size |= BM_SIZE_REGULAR
                if _is_regular($width, $height);

        #say "$width x $height is regular" if $size & BM_SIZE_REGULAR;
        #say "$width x $height is wide" if $size & BM_SIZE_WIDE;

        return $size;
}