I've had to submit a bunch of pics lately and they needed some work done. The files were jpgs and when I finished work on them I chose save as, I didn't want to effect the original file. So I selected save as and saved them as tiffs. When the files went to my desktop they were still labeled as jpegs but the files size had tripled. I tried to open them in PS shop but it said it was an unreadable jpeg. What's going on? Why can't I save a JPG as a tiff? Also is there anyway to get PS to add the file tag? I use a mac and it doesn't put jpg or tiff at the end of the file name. I need it for my online printer.