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copied!<p>It's not an issue with the application code, it's with the watermark image (PNG) itself.</p> <p>A lot of watermark examples/tutorials say to use a PNG-24 watermark, but according to a blog I've just read, they say that <code>imagecopymerge</code> does not deal with PNG-24 files very well, therefore, use PNG-8 and some special 'Save for Web' settings. I did this and it works fine now.</p> <p>Here is the relevant section about PNG types from <a href="http://salman-w.blogspot.com/2008/11/watermark-your-images-with-another.html" rel="nofollow">this blog</a>:</p> <blockquote> <p>The watermark image should be in one of the following recommended formats:</p> <ul> <li>PNG-8 (recommended)<br> Colors: 256 or less<br> Transparency: On/Off</li> <li>GIF<br> Colors: 256 or less<br> Transparency: On/Off</li> <li>JPEG<br> Colors: True color<br> Transparency: n/a</li> </ul> <p>The imagecopymerge function does not properly handle the PNG-24 images; it is therefore not recommended.</p> <p>If you are using Adobe Photoshop to create watermark images, it is recommended that you use "Save for Web" command with the following settings:</p> <pre class="lang-none prettyprint-override"><code>File Format: PNG-8, non-interlaced Color Reduction: Selective, 256 colors Dithering: Diffusion, 88% Transparency: On, Matte: None Transparency Dither: Diffusion Transparency Dither, 100% </code></pre> </blockquote> <hr> <p>And for other's benefits, this is the watermark code I have that works:</p> <pre><code><? $masterURL = 'mydomain.com/myImage.jpg'; header('content-type: image/jpeg'); $watermark = imagecreatefrompng('watermark.png'); $watermark_width = imagesx($watermark); $watermark_height = imagesy($watermark); $image = imagecreatetruecolor($watermark_width, $watermark_height); $image = imagecreatefromjpeg($masterURL); $size = getimagesize($masterURL); $dest_x = $size[0] - $watermark_width - 5; $dest_y = $size[1] - $watermark_height - 5; imagecopymerge($image, $watermark, $dest_x, $dest_y, 0, 0, $watermark_width, $watermark_height, 100); imagejpeg($image); imagedestroy($image); imagedestroy($watermark); ?> </code></pre> <p>After a bit more reading (<a href="http://salman-w.blogspot.com/2008/11/watermark-your-images-with-another.html?showComment=1345978146955#c3947848442031211061" rel="nofollow">this comment</a> on the same article), I found out that you CAN use PNG-24 watermarks but with <code>imagecopy</code> instead of <code>imagecopymerge</code>. You can replace this line:</p> <pre><code>imagecopymerge($image, $watermark, $dest_x, $dest_y, 0, 0, $watermark_width, $watermark_height, 100); </code></pre> <p>with this one:</p> <pre><code>imagecopy($image, $watermark, $dest_x, $dest_y, 0, 0, $watermark_width, $watermark_height); </code></pre> <p>Using <code>imagecopymerge</code> with PNG-8 watermarks is quite good for 'on-the-fly' watermarking, as the watermark file is tiny. If you do watermarking 'behind-the-scenes', it doesn't really matter about file size and you can get much better quality from the PNG-24 watermark, using <code>imagecopy</code>.</p> <p>I hope this helps the confused watermarkers out there.</p>

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