Customized link url for photos in Catch Everest.

Hi, I have uploaded some images to my site http://www.infinitylashes.co.uk/ but when I was clicking on them the urls were quite nasty- long and with lots of numbers and the pictures' names were not corresponding with the images (I named them randomly before uploading them to catch everest media library) eg. http://www.infinitylashes.co.uk/wp-content/uploads/2014/01/cazual-e1389302561355.gif I was trying to change the name of the pictures in the media library and manipulate with permalinks but when I clicked on the picture it said that page can't be found :/ Now I don't have any urls for my pictures. I'd appreciate if someone could explain me how to make the changes so the url is straightforward and looks nice. Thank you.