I expect that you can put anything, well almost, on a T-shirt.
E.g. you could take a pic of your own bike and print it. It is your pic.
If you wanted to put a trademarked logo/symbol or whatever you want to call it, then that is a completely different matter.
I.e. any Ducati logo from whenever would 99.99999999% for sure be subject to trademark, copyright etc.
Rightly so, most companies want to protect their brand.
A good example was the software called DucatiDiag, which I believe was contested by Ducati and is now called JPDiag.
Same software, different name. Simple as that.
Legal systems would contest that consumers may have believed, due to the Ducati part of the name, that is was a factory piece of software = consumer (and brand) protection.
I have taken heaps of pics from MotoGP and WorldSBK and have had them published and no recourse whatsoever.
If that was not the the same then there would never be a pic of any sporting event allowed to be published, which would be pretty boring.
A pic is a pic and if it is yours you want to do whatever you want with a T-shirt = fine.
If the pic or artwork is not yours then you will expose yourself to copyright/trademark issues.
It would be interesting to know how this site and many, I mean many, others not associated with the Ducati name do not infringe brand name "rules"
I am never going to lose sleep over that, but it would be interesting to know.
My guess is that, as we call it in Australia, does it pass the Pub Test, which in the context of this response, does it look like it purports to be a Ducati sanctioned/owned web site or T-shirt.