Here's a couple styles to play with. I borrowed Dave's waving style for a flag but noticed that the wrong side of the wave was the anchor. Rather than mess with Dave's carefully calculated values, I made the style for horizontally flipped flags. then reversed inside the coding. Just use Photoshop or some other editor to flip your flag horizontally - place the image in the slide list twice, select both slides and apply the style. To increase the display time, copy and paste the original after applying the style as many times as desired. Also I added a flagpole which should work with about any flag.
The second style uses any 16:9 aspect ratio image you chose as both the blurred background and the waving image. Just choose one image and apply the style.
Flag Waving 2.ptestyle
Image Waving.ptestyle