Right click on the picture(format)and select open with...and then select Choose Program.
 
From the list select Acdsee(should be under preferred programs)
 
Check the option Always use the selected program to open this kind of file.
 
Click ok, your done.
 
Now anytime you open that picture format it will open with acdsee on a double click(or single click if you prefer that setup)

Yes, I have done that, even with ACDSee set as the program to view these files it still is over ridden...wierd.

Not for me, works flawless here. What build?

Well, ok, I sorta lied. I mean, I don't have a "open with" option when I right click on an image. So I go to the file types under the Folder Options area and look at .bmp / .jpgs extenstions. They all say Open With ACDSee as the default.
 
Wierd...also, ACDSee claims that it opens all the image files in the file integration options.
 
I have XP Pro 2486
 
While I post, if I have say RC1, can I just 'upgrade' my current build to that without a 'clean install'?
Thanks guys

Go to:
 
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{e84fda7c-1d6a-45f6-b725-cb260c236066}\shellex\
 
and delete the subkey:
 
MayChangeDefaultMenu
 
Reboot. Images will now open in your default viewer by double-clicking. You can still right-click and select PREVIEW if you want to open it in Image Preview.
 
If you want to get rid of the PREVIEW menu option entirely, you can go to
 
 
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{e84fda7c-1d6a-45f6-b725-cb260c236066}\InProcServer32
 
and for the (Default) Value, change the data to the exact location of your preferred image viewer, in my case: "G:\Program Files\ACD Systems\ACDSee\ACDSee.exe"
 
Reboot. No more "Preview" option on right-click.

Thanks man, that works like a charm!

for future reference to make an open with dialog show up when you right click on a file hold the RIGHT SHIFT key then right click.