1. Go to www.photobucket.com. Either sign in if you have an account, or sign up if you don't have one.
2. Select your Photo Bucket plan. I use the free 2GB and it works fine.
3. Upload your photo(s).
4. At the top of the page you'll see an "edit" button. Click it. It will lead you to a way to edit your image.
5. Edit the image to however you want it. Don't forget to click the arrow on the right of the toolbar to see more. That is where you'll find something that says "add text".
6. Click save. It will automatically redirect you to the image. Click on the "direct link" button on the sidebar.
7. Add an image to your blog post. Click on image url and click paste. Now you have an image with your watermarked blog name!