Well, your not giving us much to go on but if it had to do with transferring them (say to a flash drive) and now their not on your computer then remember to use the "Copy or Copy To" options and not the "Move or Move To" this option will move the original from the folder and apply it to the target location.. Copy or Copy To extracts a copy of the original and sends this to the target folder retaining the original in it's location folder.. Just click on the picture(s) again and using copy, send a copy back to the original folder.. If you can't find them and you haven't done anything to the original location that you took them from (that is closed then reopened) then you can click "EDIT" then "UNDO MOVE" this will bring them from that location back to the original folder.
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them