Usage:

	if (is_uploaded_file(@$_FILES['ulimage']['tmp_name'])){
		move_uploaded_file($_FILES['ulimage']['tmp_name'], dirname(__FILE__) . "/tmp/" . $_FILES['ulimage']['name']);
		$allowed_types = array("bmp","wbmp","jpeg","jpg","gif","png","xpm");
		$pathinfo = pathinfo($_FILES['ulimage']['name']);
		if (!in_array(strtolower($pathinfo['extension']), $allowed_types))
			echo "<script>alert('Invalid file type');</script>";
		resizeImage(dirname(__FILE__) . "/tmp/" . @$_FILES['ulimage']['name'], dirname(__FILE__) . "/tmp/" . $targetfilename, $width, $height);
		$hasupload = TRUE;
	}

Image Upload And Resize Example

Code:

function resizeImage($srcimage, $destimage, $width, $height) {
		if (!file_exists(realpath($srcimage)))
			return;
		
		$srcpathinfo 	= pathinfo($srcimage);
		$srcext 		= strtolower($srcpathinfo['extension']);
		$destpathinfo 	= pathinfo($destimage);
		$destext 		= strtolower($destpathinfo['extension']);
		$size 			= getimagesize( $srcimage );				// Get the size of the original image into an array [0]=> width, [1]=> height
		$image			= null;
		$canvas 		= imagecreatetruecolor( $width, $height );	// Prepare canvas
		
		// Create a new image in the memory from the file 
		switch ($srcext) { 
			case 'wbmp':
			case 'bmp':
				$image = imagecreatefromwbmp($srcimage);
				break;
			case 'jpg':
			case 'jpeg':
				$image = imagecreatefromjpeg($srcimage);
				break;
			case 'png':
				$image = imagecreatefrompng($srcimage);
				break;
			case 'gif':
				$image = imagecreatefromgif($srcimage);
				break;
			case 'xpm':
				$image = imagecreatefromxpm($srcimage);
				break;
			default:
				return;
		}
		
		// Calculate dimensions
		$widthratio		= $size[0]/$width;
		$heightratio	= $size[1]/$height;
		$dimensions 	= array(
						'ratio' 			=> $widthratio,
						'source_cropwidth' 	=> 0,
						'source_cropheight' => 0,
						'source_offsetx' 	=> 0,
						'source_offsety' 	=> 0
						);
		
		if ($heightratio < $widthratio)
			$dimensions['ratio'] 			= $heightratio;

		// let say image is 1200*800, then:
		// widthratio = 1200/400 = 3
		// heightratio = 800/300 = 2.66
		// since there is less height than width, the max scale we can do is 2.66, then
		// the targetwidth to crop = 400 * 2.66
		// the targetheight to crop = 300 * 2.66
		// the offset width = (1200 - (2.66 * 400))/2 = 68
		// the offset height = (800 - (2.66 * 300))/2 = 1
		
		$dimensions['source_width'] 		= $size[0];
		$dimensions['source_height'] 		= $size[1];
		$dimensions['source_cropwidth'] 	= $width * $dimensions['ratio'];
		$dimensions['source_cropheight'] 	= $height * $dimensions['ratio'];
		$dimensions['source_offsetx'] 		= ($size[0] - $dimensions['source_cropwidth']) / 2;
		$dimensions['source_offsety'] 		= ($size[1] - $dimensions['source_cropheight']) / 2;
		
		imagecopyresampled($canvas, $image, 0, 0, $dimensions['source_offsetx'], $dimensions['source_offsety'], $width, $height, $dimensions['source_cropwidth'], $dimensions['source_cropheight']);
		
		switch ($destext) {
			case 'jpg':
			case 'jpeg':
				imagejpeg( $canvas, $destimage );
				break;
			case 'png':
				imagepng( $canvas, $destimage );
				break;
			case 'gif':
				imagegif( $canvas, $destimage );
				break;
			case 'wbmp':
			case 'bmp':
				imagewbmp( $canvas, $destimage );
				break;
		}
		
		imagedestroy( $canvas );
		imagedestroy( $image );
	}