The problem statement:
When linking to an image or other resource that is outside your project folder, it pops up a warning saying that if that resource moves, things might break.
The proposed solution:
When you try to link to a resource outside your project folder, offer to copy it into your resource folder first.
“Would you like to make a copy in your project folder to this file first? Yes | No”
Hitting “Yes” would make a copy in the right directory, and auto update the url that you want to use in your image path, etc. No extra dialog is necessary.