Okay, today’s lesson started out as pure frustration. The flood fill step just wasn’t working! After trying it three times, I looked to see what other settings might be interfering with my efforts, and I discovered that I had my blend mode set to “darken,” which the white wouldn’t do, of course. When I changed it to “normal,” all worked as expected – hooray! Then I had to play around with the size and placement of the photos so the actual arches weren’t ‘interrupted’, but at least I knew that my skills were up to that challenge.
I am learning so much! Thank you all for sharing your talents.