First, you need the NSURL of the image you want to share. If you're image is just in memory, you can save the image somewhere and then use that URL.
NSURL *imageURL = /* URL of your image */
Now create an UIDocumentInteractionController with the method:
UIDocumentInteractionController *documentInteractionController =
[UIDocumentInteractionController interactionControllerWithURL:imageURL];
That's it. You can go ahead and present your documentInteractionController with any of these methods:
– presentOptionsMenuFromRect:inView:animated:
– presentOptionsMenuFromBarButtonItem:animated:
– presentOpenInMenuFromRect:inView:animated:
– presentOpenInMenuFromBarButtonItem:animated:
– dismissMenuAnimated:
So now a popover will show up, listing all the apps that are willing to use your image (including iMovie if installed).
If you want to find out more about UIDocumentInteractionController, go here:
http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIDocumentInteractionController_class/Reference/Reference.html