You may my be able to zoom to 45% because a small document will be too small and 45% of a very large document will not fit on your screen. However you should be able to zoom images you open to fits your display by setting up a Open Document event handler that uses a one step action that does a menu View>Fit on Screen....
Or zoom to fit on screen the zoom out one time Ctrl+- a two step action. In either case the Zoom % will vary with document size.
Hi JJMack, thank you.
"Fit on Screen" it would be great. But I don't know how to create event handlers. I think it's necessary to do some programming?
Is there a menu on Photoshop to determine by default that all pictures should be opened with the variable size "Fit on Screen"? (Probably not, because if there was one, you would have said...)
It is very east. Created an action that has one step name the Action FitDisplay. The Click Record, Record no not steps just hit stop recording. Then use the action Pallets Fly-out menu insert menu item. Then use menu View>Fit On Screen the chick OK in the insert menu item dialog. That finishes the action. Next set up two script event handlers to use the action.
Use menu File>Scripts>ScriptEventManager. In the dialog check enable events to run Scripts/Actions and the use the pull-down menu and select event new document. Radio button Action and select the action set the you create the FitDisplay Action in and select the FitDisplay action. Then Click the ADD button. Use the pull-down menu again and select the Open Document Action Action Set Action FitDisplay Add then use the Done button.