What would be the best method to run Windows on a 2.2ghz MacBook with 4 gigs of ram? Parallels , Bootcam, or other....
You must want to run Windows for a good reason. When I switched, I used Windows a lot, because I didn't know which software was available for Mac and I didn't know how to use a lot of what software I knew was available for Mac. NOW I love OS X and prefer to use Mac, but still need to use Windows from time to time. The handiest (best) way IMO is Fusion. No reboot is necessary, it's fast and stable, and more feature-rich. I love the ability to sleep (suspend) my Windows machine and close Fusion. When I open Fusion next, BAM, there's Windows. Virtually no boot time (10 seconds, maybe?) With you having so much RAM, Fusion is probably the way to go. Even with image processing, I'll bet it'd be fast enough.
One caveat to the above: when you install Windows virtually, you've got to realize that EVERYTHING Windows-related is in actuality one huge file on your HD. So you won't be able to backup to a FAT32 external drive, for example. Also if your drive gets corrupted, it's bye-bye Windows (and Windows apps and Windows files).
There are two ways around this: first, save all files to the Mac HD, rather than the Windows My Documents folder (or what have you). Fusion bridges data between Windows and OS X, so you can seamlessly access "both" hard drive structures. This also holds for Clipboard functions. You can copy from a Windows app and paste into a Mac app. So that's one way around it; if you save all files to Mac HD, if your drive goes bad, you still have important files.
The second way around is to use BootCamp to partition your drive and install Windows, but then use Fusion to run your BootCamp partition from within OS X. This has the benefit of separate Windows files. If something corrupts, it is compartmentalized from everything else. With this method you can also choose to boot natively from your BootCamp partition if the need arises (e.g., you want to use both processors and all of your RAM on Windows tasks). The only thing you lose here is the ability to suspend your virtual machine from inside OS X, since with a bootable partition, it would be easy to corrupt if it was suspended and then booted. That's not THAT big of a deal; you just have longer startup times for Windows (still less than a minute on my MacBook).
I shied away from Parallels because of reports of slowness, instability and just overall feature-anemia. Yes, it's been around longer than Fusion and is more well-known, but those attributes don't make software better. I mean, look at Microsoft Word!
Does that answer your question?