As for the picture and some other comments I've heard here; We can't even tell who it is with a gun to his head, the face is hidden. I'm no expert but the chains look woefully inadequate for restriction, one hand looks like it's almost worked it's way out already. We can't see the hands of the gun wielder so don't know if they have callouses or not. Most reporters would be close to some kind of populated area, at least as a base. Near the base of operations would be the most likely place for a planned abduction. Populated areas often have running water and some people even keep their clothes clean.
I don't know what to make of it all but as I have also seen posted here already, it smells bad.
I don't think it sounds good, either. There's somehow something odd about it. First of all, while the letter is laden with errors and odd constructions, it seems to me as if someone has far too good a mastery of colloquial American English to have picked it up in Pakistan. The easy use of the contraction ("don't")wouldn't be something for a merely occasional non-native speaker, even somebody who used chat-rooms. I don't know any Arabic languages, so I don't know if these grammatical mistakes would be typical of an Arabic speaker or not. (People tend to preserve some of their native language structures when writing in a second language.)
I was also puzzled by Amrikan. Perhaps it was an attempt to spell Amerikan (remember, the radical left was always referring to America as Amerika).
And, as many people here have pointed out, the photograph is also a little disturbing. It's not possible to be sure that it's Pearl (who, furthermore, appears to be wearing the kind of nylon running suit or windbreaker jacket often favored by natives of Arab countries, judging from pictures I have seen). And the fact that the clean, smooth-looking hand holding the gun appears to be wearing a gold ring also indicates that we're not talking about crazed goat-herders here.