Adding watermarks to images using alpha channels

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- Adding watermarks to images using alpha channels

## Adding watermarks to images using alpha channels

Example #1 Adding watermarks to images using alpha channels

    <?php
    // Load the stamp and the photo to apply the watermark to
    $stamp = imagecreatefrompng('stamp.png');
    $im = imagecreatefromjpeg('photo.jpeg');

    // Set the margins for the stamp and get the height/width of the stamp image
    $marge_right = 10;
    $marge_bottom = 10;
    $sx = imagesx($stamp);
    $sy = imagesy($stamp);

    // Copy the stamp image onto our photo using the margin offsets and the photo
    // width to calculate positioning of the stamp.
    imagecopy($im, $stamp, imagesx($im) - $sx - $marge_right, imagesy($im) - $sy - $marge_bottom, 0, 0, imagesx($stamp), imagesy($stamp));

    // Output and free memory
    header('Content-type: image/png');
    imagepng($im);
    imagedestroy($im);
    ?>

This example is a common way to add watermarks and stamps to photos and copyrighted images. Note that the presence of an alpha channel in the stamp image as the text is anti-aliased. This is preserved during copying.