I had a feeling it is like this to prevent already posted links to the image from not working.
The majority of times we use this to rearrange sequence of uploaded photos before links are created.
As I use a description in filename of image it looks weird to not have the correct filename with the replaced image.
Perhaps one solution could be to have an option during the replace function something like ...
Replace with new image filename? Y/N
(
Note this may break any links to this image)
Feel free to move this thread to Suggestions