When students take a quiz, I sometimes include a File Upload question. I use this for problems that the students need to work out on paper to show their work. Or it's a screenshot of an activity they are doing on their computer. To view the image in Speed Grader, I have to download it to my computer, view it in an image viewer, then delete it. It's about 10-15 seconds per image, which adds up to a lot of extra clicks and time over a Speed Grading session.
For images, display a thumbnail of the image in the Speed Grader. When I click or tap on an image, a pop-up window appears showing the image at full size (or whatever size will fit in the browser window). There ought to be tools available to zoom in and out, scroll up/down/left/right, and download the image. A click on a "close" button—or just clicking away from the image—will close the popup. Ideally, this would be implemented as the same viewer that is used in the assignment Speed Grader. It would come complete with annotation tools and would allow viewing of any type of document (not just images) during quiz grading.
