Picasa is an image organizer and image viewer for organizing and editing digital photos, plus an integrated photo-sharing website, originally created by Idealab in 2002 and owned by Google since 2004. "Picasa" is a blend of the name of famed Spanish painter Pablo Picasso; the phrase mi casa for "my house", and "pic" for pictures (personalized art). In July 2004, Google acquired Picasa and began offering it as a free download. Native applications for Windows XP, Windows Vista, Windows 7 and Mac OS X (Intel only) are available through Google Labs. For Linux, Google has bundled Wine with the Windows version to create an installation package rather than write a native Linux version, but this version is severely out of date (the latest Windows version, however, can be run with Wine, see Linux section). For Windows 98, Windows Me and Windows 2000, only an older version is available. There is also an iPhoto plugin or a stand-alone program for uploading photos available for Mac OS X 10.4 and later.
Web Album alternatives
There are, however, also other programs that can upload to Picasa Web Albums. GwenView and DigiKam can upload to Picasa Web Albums when you install the kipi-plugins package and Shotwell can upload it without any plugins.
Organization and editing
For organizing photos, Picasa has file importing and tracking features, as well as tags, facial recognition, and collections for further sorting. It also offers several basic photo editing functions, including color enhancement, red eye reduction and cropping. Other features include slide shows, printing and image timelines. Images can also be prepared for external use, such as for e-mailing or printing, by reducing file size and setting up page layouts. There is also integration with online photo printing services.
Keywords
Picasa uses picasa.ini files to keep track of keywords for each image. In addition to this, Picasa attaches IPTC keyword data to JPEG files, but not to any other file format. Keywords attached to JPEG files in Picasa can be read by other image library software like Adobe Photoshop Album, Adobe Bridge, digiKam, and iPhoto.
According to Picasa Readme,Picasa can parse XMP data. However, it cannot search local files for existing XMP keywords.
Searching
Picasa has a search bar that is always visible when viewing the library. Searches are live in that displayed items are filtered as you type. The search bar will search filenames, captions, tags, folder names, and other metadata.
Picasa also supports boolean operators for searching in much the same way as Google's web search. All search terms are required by default (as with the operator "AND"), and images tagged with specified keywords can be excluded by using the hyphen (as in the boolean operator "NOT"). For example, searching for family children -friends will cause Picasa to display all images with the keywords "family" and "children", but which do not include the keyword "friends".
Picasa also has an experimental feature in the search bar where images can be searched for that contain certain colors with the "color:" operator.
Viewing
Picasa has no separate view window. There is only an "edit view" with a viewing area. Fullscreen view is available in slideshow mode, by holding down the ctrl+alt keys while in "edit view", or by pressing the Alt Gr key. This feature is also available through the context menu of Windows Explorer, and provides a way to start the Picasa editor as well.
Backup
In Picasa 2 and earlier versions, changes to pictures made in Picasa overwrite the original file, but a backup version of the original is saved in a hidden folder named "Originals" in the same folder as the original picture (.picasaoriginals on Mac OSX) .
In Picasa 3, changes to pictures made in Picasa are saved to a hidden file picasa.ini in the same folder as the original picture. This allows multiple edits to be performed without altering the original image. Viewing the picture in Picasa or using the Picasa Photo Viewer will apply modifications on the fly, whereas viewing through other programs (such as Windows XP's Photo and Fax Viewer) will display the original image. Changes can also be made permanent using the "Save" function, where the original file is backed up and the modified version is written in its place, similar to version 2.
Face recognition
On 15 August 2006, Google announced it had acquired Neven Vision whose technology can be used to search for features within photos such as people or buildings. Google applied this technology for face recognition and this functionality was launched on Picasa Web Albums on 2 September 2008.
Neven Vision incorporates several patents specifically centered around face recognition from digital photo and video images. Neven Vision's technology was among the top finishers in both the FERET 1997 and FRVT 2002 independent tests comparing the world's best face recognition technologies.
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