Different watermark image depending on size of original image

Question

I have the following code, which I sourced at http://dolcepixel.com/how-to-watermark-all-your-uploaded-images/

I need to modify the code to use a different watermark image if the original image is below a certain size.

I see there is a line of code regarding not applying the watermark if it is below 150x150 but how could this be modified to use a different watermark rather than no watermark?

<?php
//we tell the server to treat this file as if it wore an image
header('Content-type: image/jpeg');
//image file path
$img = $_GET['src'];
//watermark position
$p = $_GET['p']; if(!$p) $p = 'c';
$q = $_GET['q'];
if(!$q || $q<0 || $q>100) $q = '93';
$filetype = substr($img,strlen($img)-4,4);
$filetype = strtolower($filetype);
if($filetype == ".gif") $image = @imagecreatefromgif($img);
if($filetype == ".jpg") $image = @imagecreatefromjpeg($img);
if($filetype == ".png") $image = @imagecreatefrompng($img);
if (!$image) die();

//getting the image size for the original image
$img_w = imagesx($image);
$img_h = imagesy($image);

//if the filename has 150x150 in it's name then we don't apply the watermark
if (eregi("MTP-logo", $img)) {
    imagejpeg($image, null, $q); die();
} else {
    $watermark = @imagecreatefrompng('watermark.png');
}
/*
//if you want to use the watermark only on bigger images then use this instead of the condition above
if ($img_w < "150") {//if image width is less then 150 pixels
    imagejpeg($image, null, $q); die();
} else {
    $watermark = @imagecreatefrompng('watermark.png');
}
*/
//getting the image size for the watermark
$w_w = imagesx($watermark);
$w_h = imagesy($watermark);
if($p == "tl") {
    $dest_x = 0;
    $dest_y = 0;
} elseif ($p == "tc") {
    $dest_x = ($img_w - $w_w)/2;
    $dest_y = 0;
} elseif ($p == "tr") {
    $dest_x = $img_w - $w_w;
    $dest_y = 0;
} elseif ($p == "cl") {
    $dest_x = 0;
    $dest_y = ($img_h - $w_h)/2;
} elseif ($p == "c") {
    $dest_x = ($img_w - $w_w)/2;
    $dest_y = ($img_h - $w_h)/2;
} elseif ($p == "cr") {
    $dest_x = $img_w - $w_w;
    $dest_y = ($img_h - $w_h)/2;
} elseif ($p == "bl") {
    $dest_x = 0;
    $dest_y = $img_h - $w_h;
} elseif ($p == "bc") {
    $dest_x = ($img_w - $w_w)/2;
    $dest_y = $img_h - $w_h;
} elseif ($p == "br") {
    $dest_x = $img_w - $w_w;
    $dest_y = $img_h - $w_h;
}
imagecopy($image, $watermark, $dest_x, $dest_y, 0, 0, $w_w, $w_h);
imagejpeg($image, null, $q);
imagedestroy($image);
imagedestroy($watermark);

?>

Answer 1

Based on this (gets width and height) you can do it:

$img_w = imagesx($image);
$img_h = imagesy($image);

Remove this:

if (eregi("MTP-logo", $img)) {
    imagejpeg($image, null, $q); die();
} else {
    $watermark = @imagecreatefrompng('watermark.png');
}

Place if s based on $img_w or $img_h, like this:

if($img_w>1000)$watermark = @imagecreatefrompng('watermark1000.png');
else if($img_w>800)$watermark = @imagecreatefrompng('watermark800.png');
else if($img_w>600)$watermark = @imagecreatefrompng('watermark600.png');
else if($img_w>400)$watermark = @imagecreatefrompng('watermark400.png');
else if($img_w>200)$watermark = @imagecreatefrompng('watermark200.png');
else $watermark = @imagecreatefrompng('watermarkmini.png');