Image Library - way to change file name?

I've discovered a number of legacy files amongst my image files have "+" in the filename which seems to be bothering some requests - i.e. the image does not display (although it used to display at one time in Backdrop on the pages.

Since I have hundreds of them is there a way to change the filename by replacing the "+" with "-and-" and not end up with duplicates in the Image Library?

And while I'm here - how do you remove unwanted images from the Image Library?