I'll keep this really short. I discovered how to install CS2 from the CD. No existing Windows installations. No registry-work. No bit torrent.
You need to have wine installed before you continue. I won't cover that here, there's plenty of good documentation on that subject already. You do need to know where your "Windows c drive" is located; for me it was /home/USER/.wine/drive_c. I used wine version wine-0.9.49
Create a sub-folder under drive_c; I called mine cs2. So now I had a directory /home/USER/.wine/drive_c/cs2
Copy the CS2 CD contents into the sub-folder.
Now if you look in this folder, there is a Setup.exe that will not run; it just complains about a missing .ini file. Well that sucks, don't it? Read on!
There is another folder named Adobe(R) Photoshop(R) CS2. On my machine it was under /home/USER/.wine/drive_c/cs2/Adobe(R) Photoshop(R) CS2. Inside this folder is another setup.exe; it seems to run under wine. I had CS2 installed in under 10 minutes start to finish.
I do believe it is safe to remove the directory containing the CD's contents from your system. I renamed mine and everything still appears to work.
I do not use CS2 in my daily routine, nor my weekly routine. In fact I hardly ever use it. But I do own a copy for some web design. As such, I can't begin to tell you which plug-ins will or won't work. I can't tell you how stable it is. I can't tell you what parts of the GUI are present or absent. The only thing I can vouch for is that this is much easier than dealing with any other method I found on Google.