Pollytink,
When I want to see an enlarged pic I just press Ctrl and the + sign. It will enlarge the pic each time you press Ctrl +. Try it and see if it works for you. This has also been helpful when the print in a thread is so large that I have to scroll across the page to read it all. I just press Ctrl and the - sign and it reduces the words to a manageable size. And it is just the opposite to get back to the original size. Good luck.