Cropped Thumbnails using PHP and the GD Library

This post was published 7 years 6 months 28 days ago. There is a chance that some APIs or software versions discussed have changed since this article was written.

This code will allow you to create a thumbnail from a segment of the image. In some situations, you want to thumbnail an entire image – but other times, you may want only a piece – for example if you wish to generate square thumbnail images regardless of whether or not the original image is landscape or portrait style.

The basics are as follows:

1. Resize the image, using the $newthumb size value as the SMALLEST measurement (height in the case of landscape images, width in the case or portrait images). So if you had an original image that is 400 pixels wide and 200 pixels tall, it would set the height to 60 (since 60 is the $newthumb height we’ve used in the example below) and then resize the width down according to whatever ratio is that will contrain the proportions.
2. Trim off the extra so that the end thumb is 60×60.

[sourcecode language='php']
$orig_path = ‘/path/to/original/file/’;
$micro_path = ‘/path/to/cropped/file/’;
$imagefilename = ‘myimage.jpg’;

$size = getimagesize($orig_path.$imagefilename);

/**
* new cropped thumbnail sizes
*/
$newthumb_width = 60;
$newthumb_height = 60;

/**
* assign friendlier values to getimagesize data
*/
$orig_width = $size[0];
$orig_height= $size[1];

$width_ratio = ($newthumb_width / $orig_width );
$height_ratio = ($newthumb_height / $orig_height);

if ($orig_width > $orig_height ) {
// this is a landscape image
$crop_width = round($orig_width * $height_ratio);
$crop_height = $newthumb_height;

} elseif ($orig_width < $orig_height ) {
// this is a portrait image
$crop_height = round($orig_height * $width_ratio);
$crop_width = $newthumb_width;

} else {
// this is a square image
$crop_width = $newthumb_width;
$crop_height = $newthumb_height;
}

$source_img = imagecreatefromjpeg($orig_path.$imagefilename);
$dest_img = imagecreatetruecolor($newthumb_width,$newthumb_height);

/**
* if you want to crop from a specific area, for example, if you
* want to crop the image from the middle instead of the top left,
* you’ll need to do some more math to replace the 0,0,0,0 bits here.
*/
imagecopyresampled($dest_img, $source_img, 0 , 0 , 0, 0, $crop_width, $crop_height, $orig_width, $orig_height);
imagejpeg($dest_img, $micro_path.$imagefilename);
imagedestroy($dest_img);[/sourcecode]

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