<?php
// Set the path to the image to resize
$input_image = "aaa.jpg";
// Get the size of the original image into an array
$size = getimagesize( $input_image );
// Set the new width of the image
$thumb_width = "100";
// Calculate the height of the new image to keep the aspect ratio
$thumb_height = ( int )(( $thumb_width/$size[0] )*$size[1] );
// Create a new true color image in the memory
$thumbnail = ImageCreateTrueColor( $thumb_width, $thumb_height );
// Create a new image from file
$src_img = ImageCreateFromJPEG( $input_image );
// Create the resized image
ImageCopyResampled( $thumbnail, $src_img, 0, 0, 0, 0, $thumb_width, $thumb_height, $size[0], $size[1] );
// Save the image as resized.jpg
ImageJPEG( $thumbnail, "resized.jpg" );
// Clear the memory of the tempory image
ImageDestroy( $thumbnail );
?>