|Picture downloaded from Picasa from Jeremy King|
You start with Picasa by going to http://picasa.google.com and downloading a copy of the free program. It puts a program on your computer that can automatically look for all of the pictures on your computer and display them into the one program. It does not actually move any of the pictures, but puts a pointer to them so that you can find them all in one place. So far all you have is a program that helps you organize what is already on your computer.
The thing I find most irritating thing about Picasa is that it automatically goes and finds all of your pictures, so when you open it up you see a scrolling window on the bottom left side that automatically finds and categorizes all of the graphics on your computer. You can set it up to only look in certain folders for pictures.
First go to Tools>Folder Manager
Picasa always leaves the original of your photos the same as it was. It is a program for organizing and editing your photos. When you open a picture and do some editing of it the original is not changed and when you save it a second copy is saved so that the original stays the same.
In order to upload any pictures that you want to save find the picture or folder from the left side menu and at the top of the window that appears choose SHARE. You will be given a choice to share these pictures publicly or privately.
http://picasaweb.google.com. From here you can either search everyone's public photos with the search at the top of the page or log into your own album. Your online web album also has privacy settings. Here you can allow people to see your images, but not download them or even keep them completely private so that only you can see them when you log in.
Because Picasa is a Google program it has a connection to Blogger and so any images that are posted to a blog are also posted in Picasa online. All of the images from this blog can be found in the Picasa album from this blog.
There is some fantastic information here that goes more in depth. https://sites.google.com/site/picasaresources/faq
There is so much more that you can do with either Picasa or Flickr, but this should give you a start saving your precious photos. Picasa is made for editing, organizing, sharing and creating things with your photos.