The results that I obtained gave me some guidelines for getting the best quality animated photo images.
1. Size all images required for the animation in PSD format to the target size that will appear on the page.
2. Create the animation, and write it to animated GIF format.
3. Upload the animated image to a photo server.
4. Use the URL of the image on that server to place the image in the post.
5. Edit the HTML code of the post to specify the correct width.
I have deleted the posts that I did during my tests, so all the associated comments have gone to look for Santa at the North Pole.