Thanks much, Tim! I think the part I initially missed may have been the “ElementsByTagName” as I was struggling to understand that when I was reading other solutions that used the loop.
Pages 3 and 5 come very close to the end goal. With the +1, the tab order ends up with the images one after the other instead of image -> drop down, image -> drop down.
Would it be possible to set a loop on a second variable equal to the value attributed to the tabindex for the image, then +1 for the drop down, then +1 for the next image, etc., etc.
In the end, I may have to use the question text instead of the image and set the text off page, since sighted users don’t need the alt tag. Not the absolute best solution, since the screen reader DOES announce “graphic”, but at least the intent of the question is still operable and perceivable.