A generalization is a statement that seems to be true in most situations or for most people, but that may not be completely true in all cases.
The fact that Oswald is not holding a visible and readable receipt of purchase for the rifle (in the photograph) does not prove he does not own the rifle. Is that the sort of evidence that would convince you Oswald owned the rifle he held in the photograph taken by Marina Oswald.
Oh boy.... here he goes again.
No proof for it not being his rifle is needed, since (and I think I have mentioned this before) the mere fact that he was photographed holding a rifle does not prove that he owns the rifle. Your assumption that it is his rifle is just that.... an
assumption!
Btw... I now have a photograph of myself with a brand new Lamborghini. Following your "logic" I must be the owner of that car, so if you are interested, I can give you a good deal. Come to think of it, I also have photographs of myself in front of the Eiffel tower and on London Bridge.... Would you be interested?
Think about this example: A photograph of Dorothy Hamill wearing skates when she won the Olympic Gold medal at the Winter Olympics (1976) in Innsbruck Austria does not prove she owned the skates. However, 99.99% of people would consider she owned the skates she was wearing in the photograph. Of course there would be some nut, somewhere, who would insist that she does not (did not) own the skates. Why some nut would make that assertion is for psychiatrists to explain.
Your desperation is showing as that is a pathetic example. Although, to some extend, you seem to be on the right track. The photograph by itself does indeed not prove she owned the skates
And you are right, it is a fair and reasonable assumption that they were indeed her skates, as she was wearing them, which is of course where your example goes off the rails as Oswald was wearing a shirt (probably he owned it) and holding a rifle, that could have been owned by somebody else.
Now, how about the Lamborghini... Interested?