Image to ascii art converter (not great)

ascii.php

<?php
	if(!isset($_GET['pure'])){
?>
<style>
	pre {
		line-height: 11px;
		font-family:"Courier New", Courier, monospace;
	}
	#error {
		font-family: Arial, Helvetica, sans-serif;
		font-weight: bold;
		background-color: #FFFF99;
		border: 2px solid #DD0000;
		padding: 3px;
		text-align: center;
	}
</style>
<?php
	}

	if (!$image = @imagecreatefromjpeg($_GET['image'])){
		if (!$image = @imagecreatefrompng($_GET['image'])){
			if (!$image = @imagecreatefromgif($_GET['image'])){
				die('<div id="error">Not a valid image?</div>');
			}
		}
	}
	$X = imagesx($image)-1;
	$Y = imagesy($image)-1;

	if(isset($_GET['invert'])){
		@imagefilter($image, IMG_FILTER_NEGATE) or die('<div id="error">Image filtering failed.</div>');
	}

	if($_GET['scale'] > 0){
		$scaled = @imagecreatetruecolor(($X+1) / $_GET['scale'], ($Y+1) / $_GET['scale']) or die('<div id="error">Scaling failed (1)</div>');
		@imagecopyresampled($scaled, $image, 0, 0, 0, 0, ($X+1) / $_GET['scale'], ($Y+1) / $_GET['scale'], $X+1, $Y+1) or die('<div id="error">Scaling failed (2)</div>');
		$X = imagesx($scaled)-1;
		$Y = imagesy($scaled)-1;
		@imagedestroy($image) or die('<div id="error">Scaling failed (3)</div>');
		$image = @imagecreatetruecolor($X+1, $Y+1) or die('<div id="error">Scaling failed (4)</div>');
		@imagecopyresampled($image, $scaled, 0, 0, 0, 0, $X+1, $Y+1, $X+1, $Y+1) or die('<div id="error">Scaling failed (5)</div>');
	}

	$asciichars = array("@", "#", "%", "&", "+", "*", ";", ":", ",", ".", "`", " ");

	if(!isset($_GET['pure'])){
		echo "<pre>\n";
	}

	for ($y = 0; $y <= $Y; $y++) {
 		for ($x = 0; $x <= $X; $x++) {
			$thiscol = imagecolorat($image, $x, $y);
			$rgb = imagecolorsforindex($image, $thiscol);

			if(isset($_GET['colour'])){
				echo '<span style="color: rgb(' . $rgb['red'] . ',' . $rgb['green'] . ',' . $rgb['blue'] . ');">';
			}elseif(isset($_GET['backcolour'])){
				echo '<span style="background: rgb(' . $rgb['red'] . ',' . $rgb['green'] . ',' . $rgb['blue'] . ');">';
			}

			if(isset($_GET['plain'])){
				echo "#";
			}elseif(isset($_GET['blank'])){
				echo " ";
			}else{
				$brightness = $rgb['red'] + $rgb['green'] + $rgb['blue'];
				$charlevel = round($brightness / 69.6); //divide by number = 765/(count($asciichars)-1)
				$char = $asciichars[$charlevel];
				echo $char;
			}
		}

		if(isset($_GET['colour']) || isset($_GET['backcolour'])){
			echo '</span>';
		}
		echo "\n";
	}

	if(!isset($_GET['pure'])){
		echo '</pre>';
	}

	imagedestroy($image);
?>