To learn how to use pictures frames I first added a picture frame to a blank page and experimented with different ways of adding images and scaling. moving within the frame etc. Happy with how it worked. I then when on to add a picture frame to a Master Page, and the behavour was different.
I have created a picture frame on a master page and then on a new page based on the master page I Placed a picture into the master frame. I then dbl clicked on the image went to Properties to select “Scale to Min fit”. I observed the following issues.
1. None stays selected as well as Scale to Min Fit option
2. Click on None and it deselects
3. Click on done and nothing happens
4. Reselect properties and None again selected.
5. The size slider bar adjusts the scale no problem.
6. Right click paste as content not available either
Picture frame on a page works as expected