<?php

function imageResize($width, $height, $target) {

//takes the larger size of the width and height and applies the  
formula accordingly...this is so this script will work  
dynamically with any size image

if ($width > $height) {
$percentage = ($target / $width);
} else {
$percentage = ($target / $height);
}

//gets the new value and applies the percentage, then rounds the value
$width = round($width * $percentage);
$height = round($height * $percentage);

//returns the new sizes in html image tag format...this is so you
can plug this function inside an image tag and just get the

return "width=\"$width\" height=\"$height\"";

}

?>
//Then in the HTML:
<?php

//get the image size of the picture and load it into an array
$mysock = getimagesize("images/sock001.jpg");

?>

<!-using a standard html image tag, where you would have the  
width and height, insert your new imageResize() function with  
the correct attributes -->

<img src="images/sock001.jpg" <?php imageResize($mysock[0],  
$mysock[1], 150); ?>>

http://www.sitepoint.com/article/image-resizing-php

get the image size and reduces it dynamically

image resize dynamically

resize, image

PHP