Here are the steps that I used to add a Flickr gadget to my BLOG site.
1. Have an account on Flickr.
2. From your account on Flickr, go to Tools page (under Upload Photos section).
3. Select build a badge from the Display Flickr photos or video on your website section on the right.
4. Walk through the steps needed to create your badge on Flickr. At the end, you will see a preview of the badge as well as a box containing the necessary code.
5. Copy all of the code displayed in the box at the bottom of the preview screen.
6. Go to your Blogger.com site.
7. Select the Layout tab.
8. Select one of the add a Gadget links on your page.
9. Select HTML\JAVA gadget.
10. Title your gadget, and paste the code from the Flickr page into the content box of the gadget.
11. After saving, you can select preview your Blog to see the new gadget displayed.
12. Play around with them, and have fun.