Wakefield express used to sell prints, pre super league not a problem as far as I know. Might be a good place to start.

Sadly The Wakefield express don't have any pics of Wally Lewis,
I called them a couple of years ago (trying to do the same as the OP)

When Wally left to go home he asked for some pictures of his time @ trin, they gave him all the pics they had and the negatives (this is was the WE told me)

It does make sense too as there are only a hand full of pics with Lewis wearing the RW&B in existence

I was suggesting you ask for their help rather than rip off the ones they have.
Asking may get better results.