iPhone: cached profile images from the web - how to find out that remote image changed?

Question

I'm loading profile pictures from Facebook, cache them on disk and load them into cells of a UITableView.

Now I'm wondering, how I can find out when someone has changed his/her profile picture on Facebook that I have to load the new image from the web instead of using the one cached disk.

The url of the image is always the same. Is there a lightweight way of doing this without downloading the image and comparing it to the local file?

Answer 1

From my checking, the facebook profile url will change whenever the user changes his profile image. You can check it yourself, but there is no documentation for it. Use it with your own risk:)