Well, I am trying to figure out my idea, and here is my opinion -- Vires in Numeris or Strength in Numbers have been connected to bitcoins since day one.
I owned a shirt with a bitcoin logo and the quote on top. But do you still have the physical picture with you?
Judging it by seeing the low-resolution image of it, it seems like it is a sort of design and not intended to keep or store the value of bitcoin with a Private Key. But we will never know as people in cryptocurrencies are ^weird ^{[no offense]}. Possibly that they will perhaps have put private keys on it. So, did you try to check if the photo has a set of layers? Perhaps there will be a layer between the surfaces that hides the private key combination.