i saw this topic a wile ago:
http://newsgroup.xnview.com/viewtopic.php?t=16434
I use Xnview (1.95.4) as a way for browsing high amount of scanned images.
These images rarely are the window size, so i use the "Fit image to window, large only" function in order to view them.
If i need to Zoom the image, i click the "Zoom function" icon.
Problem is: That if i want to keep the Zoom ratio for the next image, i MUST click into the "Lock Zoom" option, but if i close the Xnview window and open it again, the program keeps that locked Zoom ratio. (Quite obvious if you clicked the "Lock Zoom" isn't it?
).So, my suggestion is to be able to use the "Fit image to window, large only" option as a default... but that if you want to zoom into an image, the program locks the zoom while the xnview windows is open.
And return to the default option ("Fit image to window, large only") if the program is closed and opened again.
That option could be called something like: "Fit to window, large only when opened and keep zoom ratio IF ZOOMED for the next images".
Thanks again!
P.D. I also agree with the "Keep zoom for this session only"
rfrank
Hello !
0 : The zoom locking is kept through the sessions (standard behaviour). 
1 : The zoom locking is kept during the current session only (like in the old 1.8… versions)