Actually, the BlackBerry is excellent at many of the same things Sidekick 2 can do -- there are many things the 8700r can do better than Sidekick -- but one just need to overcome a learning curve (switching between PC and Mac entails a learning curve). Chatting with people works very well on BlackBerry too, just like a sidekick, but you need third-party software.
One of the many ways to download a JPEG to the 8700, just email the JPEG as an attachment to your BlackBerry, open the attachment, and save. (You can save either the reduced-size version or the full size version). It will now show up in the BlackBerry photo album.
For more information, see: Why BlackBerry?
And this: BlackBerry Versus Sidekick