Picasa
Picasa is a digital photo organizer and editor, and when you add to it the Picasa Web Albums service, you have a terrific all-in-one set of tools to make managing your digital photo collection very easy. It is available for Windows, Mac (Intel Macs only) and Linux computers, and it can easily replace, or at least complement the native imaging programs that come with Windows machines (Windows Photo Gallery) and Macintosh’s (iPhoto). And while Flickr is probably a bit more mature in the online photo sharing service market, Picasa Web Albums is at least competitive. There is even an uploader program that is stand-alone or works as an iPhoto plugin, which makes it a breeze to get your images shared on the web. You also have the option of making images private to only certain individuals that you designate via email. Picasa continuously scans your hard drive for new images that you add to your computer, and it also works as an importer for most digital cameras. It provides many of the basic features for editing images such as resizing, eliminating red-eye, and even straightening and cropping images.
If you would like to integrate Picasa and Flickr you can install a button to do a one-click upload to your Flickr account. You need to download the Flickr Uploader program from the tools page. Then you will need to install the picasa2flickr plugin. The installation (instructions are here) copies a file with a .pbz extension so you need to install Picasa and the Flickr uploader first. Picasa has quickly become a favorite program in the New Media Center. We think it should be part of your toolkit.
[...] some might argue that there isn’t anything, but several at least come close. We highly recommend Google’s Picasa (also available for the Mac) which is similar to iPhoto, offers similar functionality, and is free [...]