Blogger has just added a new slideshow option to the page elements menu. I've played with it a little and I still prefer the Coolstuff option that I wrote about here. With this slideshow I can customize the size and make it a little bit bigger. On the other hand, with the page element option I don't get the black background, I have more options and it is very quick and easy to change. I have placed one of each type on my sidebar for comparison.
The new page element slideshow will let you display pictures from Flickr and Photobucket besides Picasa. You can show your own pictures or pick a key word. I picked Flickr with key word Christmas Tree.
If you want to use a specific feed you can do so very easily by typing in your user name if you have a Picasa album. When I typed in my user name with the Picasa option it then brought up a list of all my public albums. When I selected Flickr and put in my user name nothing happened. I had to chose the "Other" option and then open a new window so I could go to Flickr to get my feed address. When I clicked on the orange feed icon at the bottom of my picture page the url got cut off on my google page. To solve this I had to right click on the feed link and select copy and then paste it in the feed line. I also could not pick a single album, my feed includes all of my pictures so I could not show my garden pictures at Flickr without also showing my genealogy picures. Flickr works great for keyword display and if you wanted to select just certain pictures of your own you could give them all a very unique tag that no one else would use. I don't have a Photobucket account so I didn't try doing anything with a specific feed. The keyword option didn't work with "Christmas Tree" but did work with Sunset and Blue.
Play with it and share some of your favorite pictures.
When I redecorated for Christmas my purple widget with the feed from my genealogy blog just didn't look very good so I opted for the feed option from the page elements menu. It was very easy. It isn't great looking and you are limited to 5 posts but it does the job. I don't like that it doesn't provide a link to the main page but only to specific posts.