There is a simpler way to do that.
right click on the resized image, copy, then batch select the rest of the photos, right click, and choose paste attributes.
Also, project>project settings>general and click on 'scale clips to project dimensions when adding to sequence' This way, all y'alls pitchers gonna be the right size.
And one last tip about photo slideshows, if ya didn't know. Edit>Preferences>General>still images and set your auto-import time. This way, when your importing stills and you want them to be a uniform, say, 210 frames, you can stick that in, and that's how long they'll automatically be.
Get to it, and good luck with future slideshows.