caching dynamic thumbnail

just would like to confirm here whether thumbnail images that i generated dynamically with gd is cached by browsers. a) i have a html frontend to call the php script that does that thumbnail. this html file, say, view.htm contains these lines: <html> <img src="thumb.php?image=../images/001.jpg&x=150&resize=1"> </html> b) the thumbnailing works perfectly. but is this thumbnail cached inside my browser. how do i find this out ? c) if the answer to question b) above is 'No', is it a good idea to generate thumbnails dynamically but PHYSICALLY writing it to disk (with extra checking of course; is the thumb previously was available, is it the desired size etc etc) please advise. -- roger __________________________________________________ Do You Yahoo!? Sign up for SBC Yahoo! Dial - First Month Free http://sbc.yahoo.com