Yes, you can, in your CommBox signage portal https://signage.commbox.com.au select 'Playlists' on the left side of the screen and open the playlist with the images you would like to change. By ticking the boxes on left you are able to override the pervious fit,fill, stretch settings of all the selected items. Then select in the box next to delete the option to fit, stretch or fill which will override your previous settings.