I think we all agree that trying to give credit when you can is a nice courtesy. Or keeping it open and saying you don't know where they came from and "let me know if you do"...
Problem is, a lot of times you may credit someone who just took them from somewhere else who took them from somewhere else who scanned them from a manual. Who gets the credit, the guy who has a scanner, the person who published the manual, or the last guy to copy them? Skull, I see even your first diagram says edited by 650motorcycles... and he must have got it from somewhere because he didn't create it from scratch since it’s an edit. So for that first image, at the minimum, the path went: publisher creates it, "bob" scans and edits, jayel saves and posts to 650 rider, you save it and post here.
So unless it's a picture someone took, a new diagram someone drew up, or another new and original document that hasn't been whored all over the internet, I don't worry too much over trying to find the original source of something. Not trying to sound like an ass… (see the first sentence of this post)
