Fetch an image file kept at server using JS in rails

I am using rails v 3.2 and ruby v - 1.9. I have been trying to work this out and after a lot of googling can't find a solution. If there are certain files created at runtime at the server side, how do i fetch them and show them to the user i'e; the client side using JS. please note that there can be any number of files and are mainly images and all of them need to be shown at once. any help would be great.