Create thumbnail with PHP (1)
PHP can be used to create and manipulate image files in a variety of different image formats. This post shows how to create thumbnail image in the same directory as the original image. Instead of GD library, I used utilities from ImageMagick suite of tools so your PHP shouldn't have a GD module installed. convert with "-channel a" option will save transparency of the PNG and GIF images.
If you are looking for GD version of PHP thumbnail function, please see Create thumbnail with PHP (2).
/**
* function creates a thumbnail image in the same directory with the prefix 'tn'
* thumb should fit to the defined box (second parameter)
* only bigger images are processed, while smaller images are just copied
* function preserves PNG and GIF transparency
*
* @param string $image1_path - full path to the image
* @param integer $box - box dimension
*/
function create_thumb($image1_path, $box=200){
// get image size
$identify = shell_exec("identify $image1_path");
// read image geometry
preg_match('/(\d+)x(\d+)/', $identify, $matches);
$g1 = $matches[0]; // image geometry
$width1 = $matches[1]; // image width
$height1 = $matches[2]; // image height
// prepare thumb name in the same directory with prefix 'tn'
$image2_path = dirname($image1_path) . '/tn_' .basename($image1_path);
// make image smaller if doesn't fit to the box
if ($width1 > $box || $height1 > $box){
// set the largest dimension
$width2 = $height2 = $box;
// calculate smaller thumb dimension (proportional)
if ($width1 < $height1) $width2 = round(($box / $height1) * $width1);
else $height2 = round(($box / $width1) * $height1);
// set thumbnail geometry
$g2 = $width2 .'x' .$height2;
// save thumbnail image to the file
system("convert -channel a -size $g1 $image1_path -resize $g2 $image2_path");
}
// else just copy the image
else copy($image1_path, $image2_path);
}
I also wrote Resize images with PHP where you can read about resizing all JPG images inside a current directory. After saving images from my camera to the computer, I needed a tool to prepare images for the Web upload. With small command line PHP script, images are converted to the lower resolution and saved to the separate subdirectory.
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- Create thumbnail with PHP (2)
- Resize images with PHP script
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