here’s a great tip i found on php.net I found that I didn’t want to forget
You can use the Header command to force a browser to use fresh content (no caching).
However, this only works for the HTML code your code generates. When you have updated images for example (with the same filename) then there’s a chance that these are still cached.
The easiest way to solve this problem I found is changing:
<? print "<img src='yourfile.jpg'>"; ?> into: <? print "<<mg src='yourfile.jpg?".time()."'>"; ?> This adds an unique number to the url and wont hurt at all.