Ok so here's the problem... I've got it all setup like so...

PHP Code:

Header ("Content-type: image/png");
$img_handle = imageCreateFromPNG("somewhereonawebsite");
$color = ImageColorAllocate ($img_handle, 0, 0, 0);
ImageString ($img_handle, 5, 370, 4,  "$test", $color);
ImageString ($img_handle, 5, 370, 21,  "$blah", $color);
ImageString ($img_handle, 5, 383, 42,  "$somethingelse", $color);
ImagePng ($img_handle);
ImageDestroy ($img_handle); 


there are no errors or anything (the code is not the problem)

What I'm trying to figure out is if I can have this image as a .png instead
http://website.com/image.php?id=1 (<--- example of non .png image- what I don't want)

Can I instead call it as a .png image
http://website.com/myimg.png (<--- example of what I want it to become)
so I can put it on forums? The "id" is important to gather the necessary info ($test, $blah, and $somethingelse). So it isn't like your typical dynamic image (like those that display ip)... at least I don't think so...

Using htaccess url rewriting (mod_rewrite) you can do this to rewrite the url string so that myimage1.png will become image.php?id=1

RewriteEngine On
RewriteRule ^myimage(\d+).png$ image\.php?id=$1 [L]

hmmm... yeah I figured it'd be something like that, but just one thing

I've got 100s of "id"s and well I don't want to create 100s of files for each individual. Is there any way around that?

Just target the same page every time:

PHP Code:

<?php
$number = $_GET['id'];
?>
<img src="http://www.webmaster-talk.com/images/image<?=$number;?>.png">

Does this answer your question?

I'd like to be able to have it like one of those things people have in their forum signatures...

like those from danasoft
http://www.danasoft.com/citysign.jpg
rather than
http://www.danasoft.com/something.php?id=12345 which don't show up on forums (it only shows up on webmaster-talk forums =P but nowhere else)

I wonder how they do it

Surely they use url rewrite too, and there is a script below the citysign.jpg that compare the ip address of the request to a location DB.
It's no big deal then to create the image and send it back.

I tend to believe that the .jpg is important to IE.
I know that IE don't follow the content-type header blindly.
If you create an image, and send just the header "output-type", you will be asked to save the picture.
But rename the script in .jpg, or use url rewrite, and IE will display it.
That little bugger...

So, yeah, map an precise url schema to your script, passing a parameter like MrGraphic and WayFarer explained you, and just make sure that you use a .jpg extension in the mapped url .
Then you should be good.