Sometimes when I browse the art/texture forum, I hear reference to selling the texture item and a texture image.

I'm not sure I got this right, but does that mean that they're transfering the texture through an item?

That might be a valid assumption. However different people use these terms to designate different things. The matter is further complicated in that people have different abilities to speak and understand the chosen languages. I'd advise you to spell out exactly what you are selling or buying in any negotiation to avoid confusion. It's much easier to work out the details before you conduct a deal, than afterwords.