<?php
	$img = imagecreatefromjpeg("/tmp/fmQPg3ubOC0.jpg");
	$img = imagecreatefrompng("http://flaticons.net/gd/download-png.php?size=256&padding=0&icon=icons/Sports/Heart.png&in=Heart.png&bgShape=&bgColorR=255&bgColorG=255&bgColorB=255&iconColorR=255&iconColorG=41&iconColorB=248");
	
	$img = image_resize($img, 19, 19);
	imagedither($img);
	imagepng($img, "/tmp/out.png");
	
	function imagedither($img) {
		$w = imagesx($img);
		$h = imagesy($img);
		
		$lum_data = array();
		for ($y = 0; $y < $h; ++$y) {
			for ($x = 0; $x < $w; ++$x) {
				$color = imagecolorat($img, $x, $y);
				
				$a = $color >> 24 & 0xFF;
				if ($a > 0) {
					$r = $g = $b = 0xFF;
				} else {
					$r = $color >> 16 & 0xFF;
					$g = $color >>  8 & 0xFF;
					$b = $color       & 0xFF;
				}
				$lum_data[] = floor($r * 0.299 + $g * 0.587 + $b * 0.114);
			}
		}
		
		$pixels = count($lum_data);
		for ($i = 0; $i < $pixels; ++$i) {
			$new_pixel = $lum_data[$i] < 129 ? 0 : 0xFF;
			$err = floor(($lum_data[$i] - $new_pixel) / 16);
			$lum_data[$i] = $new_pixel;
			
			if ($i + 1 < $pixels) {
				$lum_data[$i + 1] += $err * 7;
				
				if ($i + $w - 1 < $pixels) {
					$lum_data[$i + $w - 1] += $err * 3;
					if ($i + $w < $pixels) {
						$lum_data[$i + $w] += $err * 5;
						if ($i + $w + 1 < $pixels)
							$lum_data[$i + $w + 1] += $err * 1;
					}
				}
			}
		}
		
		for ($i = 0; $i < $pixels; ++$i) {
			$y = floor($i / $w);
			$x = $i - $y * $w;
			
			$c = $lum_data[$i] < 129 ? 0 : 0xFFFFFF;
			
			imageline($img, $x, $y, $x, $y, $c);
		}
		
		
	}
	
	function image_resize($img, $width, $height) {
		$new_img = imagecreatetruecolor($width, $height);
		imagecopyresampled($new_img, $img, 0, 0, 0, 0, $width, $height, imagesx($img), imagesy($img));
		return $new_img;
	}