How to create a dynamic image that updates when requested?

So I'm trying to make my own forum signature generator for some friends, and I've gotten most of the work done. My real issue now is refreshing the information when the image is requested from my server.

I have almost no clue how to even go about it, so I'm sorry if my question is poorly written. Basically, I'm looking for someone to push me in开发者_如何转开发 the right direction on how to have the image refresh from the datasource when it gets requested, but only if it has been more than 5 minutes to prevent an overload.

Thank you. I'll post code here, as I try to make it work once I get my start.

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You will have to create a new HTTP handler. Check out this msdn post.