This is what happens. I have reported this to Telerik
The title of the Image is used for the URL.
So when you have change a second image title to the same as the first image title the url will automatically change as well.
In order to prevent this you need to give the second image an different url manually. All the way to the bottom.
Kind of hard to explain, better see the screencast
I don't know who thoght this up but at least its an immediate workaround. I recomanded to Telerik to at least have the URL shown on the top under the title.
Hope this helps