Force Update on Cached Images

I have been using PHP scripts that dynamically create images, but the problem is, these images are cached. Is there a way I can force the browser to update the cache on each view?

 

The header() function - see php.net

 

An easier way... change the URL to the image based on a randomly generated string, example:

http://www.example.com/images/image.png?randomstr=787dsa1

Code (markup):

That will make the browser reload the image every time (except the randomly generated string will be the same two times in a row which is almost impossible).

Richard

 

you must edit http header

header("Cache-Control: no-cache, must-revalidate");