Thanky you Oleg,
I find usefull to adjust feed RSS script to allow image inclusion, because Google and Bing see RSS submission as a update to sitemap submission and in my experience, they grab new RSS for sure and add URLs , while my experiments with new URLs submitted via sitemap were less satisfactory.
RSS for them is more for Fresh content, while Sitemap is for overall content.
This somehow guarantees the new URL gets into engine memory.
As I said, very nice to have.
PS. If RSS feed is placed into Google Webmaster , at Other Resources /Custom Search Engine / Indexes / URL connected to a HUB page.
In this case, Google will add to index first the URLs from Hub, then will grab the sitemaps below, in Sitemaps URL.