I don't know about where emails are permanently stored, I doubt something like that is present either on PB or BB. If your email is on BB and you bridge your PB to it, then the email should shown under messages. All messages should be present right there.
Now if you have deleted a message either on the BB (using delete all prior functions) or on your PC/Mac they will not be available anywhere, this also will happen if you delete messages using PB by clicking delete on 'handheld + inbox'.
About the picture- if you have saved the pic from the email then it should be under the pictures/downloads/document--- either of these folders.
Good luck !!
My guess is that you have deleted the original files (that came to your inbox first) and thus can't find them any longer on BB or PB (even bridged).
The attachments to your emails are stored on your BB, and can be accessed on the PB using the "bridge files" app. If you've opened the attachments, they should be stored in the following folder:
The files are listed in alphabetical order by filename. So if you have a lot of files, it'll be easier if you know the filename of the attachment you're looking for.
