Mostly doing this because Indigo has already linked what seems to be a good answer, but nobody has answered.
This is a very comprehensive list. Pictures would probably be available in the ORAS strategy guide.
commented Jul 5 by !'•-Indigo-•'!
I know that the linked guide doesn't contain any images, but the guide is very descriptive, so it shouldn't be that hard to find the items.
If you really do need pictures, however, I could try to find images for each of the routes and circle where the item(s) should be located.
Source: The mastermind known as Indigo.