grepping the right thing

Hey guys, I have a ton of of jpg filenames in a text document, I need to grep the fileames to get them somewhere else, and they all have really long numerical filenames. But the nice thing is, since this is for a website, they all start with "https://" and finish with a ".jpg", but not all the filenames are the same length, so doing the ".{0,0}https:.{0,number}" doesn't always give me the right number of characters to get the whole filename. Any solutions? (if this is complicated ill add pictures...)