Set a Nokia Map as your Facebook Timeline cover image.
This is the source for the website covermap.me. We first use the Facebook PHP SDK to log the user in. Then there's some JS to let the user position an interactive map (with an integrated search) created with the Nokia Maps JS API and some PHP to grab the same map area as a static image using the Nokia RESTful Maps API.
After that, the image is downloaded, a watermark is added using GD then it's uploaded to Facebook.
Finally, the user is redirected to a URL on Facebook where they can confirm the change in cover image.
For a better description of the interesting bits, read this blog post
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The only prerequisite on the server side is to have GD enabled.
Visit the Facebook Developers site to create an app: https://developers.facebook.com/apps/
Everything under /src/ is the Facebook PHP SDK. You should use the most up-to-date version.
Visit the Nokia Developers site to create an app: http://api.developer.nokia.com/
In config.php, enter your Facebook and Nokia App IDs and secrets.
This project's here mostly so people can grab whatever bits of code they want out of it. I'm not a particularly great PHP developer so it's a bit scrappy and old-fashioned. It still works, however.
The most useful sections are probably the bits that let you go between an interactive map and a static map.