Thanks.. I never thought about Rogozhin's reaction to the Holbein picture as taking offense at the suffering of Christ. I think because I personally look on such suffering as noble, I was always seeing it that way even through other character's eyes. I saw Rogozhin's attraction to the picture even while it was making him lose his faith, as the obsession with one's doubt over their faith. (Probably another personal interpretation.)
When Myshkin said, "You want to exchange crosses? Certainly, Parfyon, I am delighted. We will be brothers!", I took this as an innocent invitation of friendship on his part. As Rogozhin's response was, "the same mistrustfulness, the same bitter, almost ironical smile" I thought that Rogozhin was merely playing along with Myshkin mockingly, all along treating Myshkin's invitation as a childlike naivete.
I wasn't sure how to tag quotes and insert them into my reply, do you just copy and paste? Of course I tried just clicking on "quote" but I still wasn't able to highlight anything.