Since I upgraded to WP 3.6.1 the carousel image button did not work (it was there, but when you chose your image from the library and clicked insert into post, the image url link did not show up in the image link field).
I uploaded the image I wanted to use to the media library, then copied and pasted the image url into the image field and submitted and it worked.
I am not a coder so I don’t know how to fix it, but I was able to update my images for the carousel.