Dynamic <IMG>

Wed Aug 16 20:28:46 EDT 2000

On Wed, 16 Aug 2000, Ron Peterson wrote:
>I'd better confirm that this was indeed the problem before my inbox
>explodes.  :-)  I was under the mistaken impression that you only
>did this when you wanted to send an image to a browser naked and
>alone.
>
>So things work now, but not really.  Now I have to figure out why
>even dynamically generated images get cached by the browser, and
>what do I do about it.  Bleh.

Think about what happens when you do want to go to a webpage. Your
browser sends a request with a URL to the webserver to send the file
at that URL. The browser parses the HTML returned by the server, like

    <html><body>
    <img src="http://www.foo.org/image.png">
    </body></html>

When the browser sees this, it needs to make a request to also get the
"file" at http://www.foo.org/image.png. Then the browser "renders" the
webpage by putting the image in place in your browser window. So it's
just like a separate request for a "naked" image. The reason your
browser might cache the dynamically generated image is it doesn't
recognize it as a dynamic script, just another file that's sent (maybe
that's a tautology? :)

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