That's a pretty difficult question and I don't think any of us will have the truth (apart from probably Travis Smith and the guys from Opeth). Anyway, I assume it has to do with the concept of the album. In it there's death, blood and feelings against religion. The reddish colour of the cover I think would stand for blood, and the mourning woman at the front, for death (she's wearing black --some people may think she's Melinda herself--). There's a cross which could also refer to death (its religious connections are also obvious), and the whole scene is set in a forest (we can see leaves all around the cover, and also a lake). The reflection of the cross is not another cross, but a female figure. I don't think she's the mother of Jesus; in fact, I think she's Melinda, for she also dies in the story. now she must be crying for her lover, who also dies, and the red roses next to her can represent their love, the reason why he came back after 15 years.
The second question: I do not know if one can get a dedicated pic from the band. It would be cool actually, and I think we Opethians deserve it! I'll try to get some signatures at my next Opeth concert.