Browser cache

[Anon]

I've been playing around with creating JPEGs in PHP and wrote a little script to create an image of a text string argument. the problem is, when it displays the image, I have to refresh once since it's displaying the file from the browser cache. I have it echo an IMG tag with src="z.jpg" and z.jpg changes each time but Internet Explorer uses the cached version so I have to refresh to show the new text.

is there a way I can get IE to not look at the cache? I thought if the URL was different it wouldn't, and the URL is different because the query string to the PHP script is different but it's not working

[badman]

sure there is!
try this on first line of all your pages where you dont want browser to cache.Header has to be sent as the first output to a browser, else you get error as "headers already sent...."

header ("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
or

header ("Pragma: no-cache"); // HTTP/1.0
cheers!

[Anon]

thanks for the reply. I tried that, but IE still shows the cached image file until I reload the page. what else could be causing this?