You can do this by follwing the below steps.
1.Go to your friend's Scrapbook and click on Add Photo button.
2.A pop up will come on your screen. In the left bar you can see three options Upload a new Image, Add from Picasa album, Add image from website url ( This feature already exists ).
For the first option, you can directly upload an image from your computer and can than save it to one of your Picasa Web Albums also for future use.
3.Click on second option in left bar to add an existing image from your Picasa Web Album.
4.Select one of your album, you can than zoom the album to view pics in high resolution.
5.Once you click on the image, it shows a preview of image incase you don't like the pic you can choose another one.
