What if Dr. Seuss wrote The Call of Cthulhu? (UPDATED)
To elaborate on "terrible" - 1. The large image displays full size so that you have to scroll vertically and horizontally to see it, 2. You have to scroll blindly to figure out how to close the image and get back to the page, 3. By the time you manage that, you've lost your place. The workaround is to right-click (control-click on Mac) and select "Open in New Tab" from the context menu. Clicking with a modifier key (ie. command-click) doesn't work since your image viewing popup captures it.
Related: cool thoughts