Flickr vs. Picasa — What's the Difference?

Flickr (pronounced "flicker" pronunciation ) is an American image hosting and video hosting service, as well as an online community. It was created by Ludicorp in 2004 and is a popular way for amateur and professional photographers to host high-resolution photos.

Picasa is a discontinued, cross-platform image organizer and image viewer for organizing and editing digital photos, integrated with a now defunct photo-sharing website, originally created by a company named Lifescape (which at that time was incubated by Idealab) in 2002. "Picasa" is a blend of the name of Spanish painter Pablo Picasso, the phrase mi casa (Spanish for "my house") and "pic" for pictures.Native applications for Windows XP, Windows Vista, Windows 7, and Mac OS X (Intel only) were available, and for Linux, the Windows version was bundled with Wine.