Is it possible that even though you believe the trees in the images are not ID-able to the species level, perhaps an observer might know the species really well, even in terms of how it looks from a distance, and they may also be aware of what grows in that area well enough to have a pretty good or excellent idea of what it is they are shooting from the moving vehicle?
You can always just ask them in a comment, “How did you ID-ed this tree?”
The observer should also at least jot down in Notes that “this observation is for the tree in the middle”, or “the tallest of these trees” or something like, that so you can tell which tree they mean.