/**
 * Creates function imagecreatefrombmp, since PHP doesn't have one
 * @return resource An image identifier, similar to imagecreatefrompng
 * @param string $filename Path to the BMP image
 * @see imagecreatefrompng
 * @author Glen Solsberry <[email protected]>
 */
if (!function_exists("imagecreatefrombmp")) {
	function imagecreatefrombmp( $filename ) {
		$file = fopen( $filename, "rb" );
		$read = fread( $file, 10 );
		while( !feof( $file ) && $read != "" )
		{
			$read .= fread( $file, 1024 );
		}
		$temp = unpack( "H*", $read );
		$hex = $temp[1];
		$header = substr( $hex, 0, 104 );
		$body = str_split( substr( $hex, 108 ), 6 );
		if( substr( $header, 0, 4 ) == "424d" )
		{
			$header = substr( $header, 4 );
			// Remove some stuff?
			$header = substr( $header, 32 );
			// Get the width
			$width = hexdec( substr( $header, 0, 2 ) );
			// Remove some stuff?
			$header = substr( $header, 8 );
			// Get the height
			$height = hexdec( substr( $header, 0, 2 ) );
			unset( $header );
		}
		$x = 0;
		$y = 1;
		$image = imagecreatetruecolor( $width, $height );
		foreach( $body as $rgb )
		{
			$r = hexdec( substr( $rgb, 4, 2 ) );
			$g = hexdec( substr( $rgb, 2, 2 ) );
			$b = hexdec( substr( $rgb, 0, 2 ) );
			$color = imagecolorallocate( $image, $r, $g, $b );
			imagesetpixel( $image, $x, $height-$y, $color );
			$x++;
			if( $x >= $width )
			{
				$x = 0;
				$y++;
			}
		}
		return $image;
	}
}

Since PHP doesn't have a builtin imagecreatefrombmp, this allows users to upload bmp files and you can handle them and create a different image type from it.

imagecreatefrombmp

image

PHP