Frustratingly, Picasa has been folded by Google into Google Photos, but Google Photos no longer allows RSS feeds or even embedding a slideshow into another website. Even if that website is blogger, which is within the Google family. Sort of classic Google, really - once you get used to an application or piece of software it gets terminated, and even while it's supported it doesn't really connect well to the other Google products.
So, back to flickr. In truth I haven't uploaded anything to Flickr in a long time, and the embedded images leave a few things to be desired. But it's what's available.
