Picasa is a photo organizer program produced by Google. It is available as a free download for Windows XP or 2000, and there is also a version available that runs on Linux. It's primary use is to catalog and browse collections of photos, but it also includes limited photo editing capabilites, and a whole slew of associated features such as producing CDs of images, uploading them, blogging about them, or printing them.

Picasa also works with other Google programs and services, such as Blogger (blogs!), PicasaWeb (online photo albums) and Google Earth (program for browsing aerial photos of the whole earth) to provide a very full photo management package.

Keep up to date on the latest available information about Picasa via the Documenting Picasa Blog.

Google resources for Picasa

Google resources for Picasa for Linux

Picasa for Linux is available for x86 based Linux distributions. It is a currently a "Google Labs" product (a "beta" release). There are a few features of the Windows based product that are not available on Linux, notably CD production, and sound in slideshows.

Independent Resources about Picasa

Unofficial blogs about Picasa

Searches about Picasa on various specialist sites

Google Blog entries about Picasa

Press Releases

Glossary

People

The members of the Picasa Team at Google are not well known, but occasionally names are mentioned. At the time of the Google purchase in summer 2004, the company reportedly had 18 employees. Many of them transitioned to work at Google, working in Santa Monica, California.

At the time of the launch of Picasa 2.0 in January 2005, the following team photo collage was published, showing 17 photos, but the names are too small to make out.

Photos of team members are also used at random on the front page of hello.com, as follows:

Lars Perkins

Tara Morrison

"happy"

Todd

Thanks to Tara Morrison's blog, there's also a Picasa team photo from May 2003, and from Prakash Chandran, a whole album from when Picasa 2 shipped.

Jobs

Standards Documents

Although there is precious little documentation specifically about Picasa, the program does make use of a number of standards which are well documented.

Included Software Libraries

Picasa was not all written from scratch (and it's apparently up to 500K lines of code) - it includes a number of other pieces of software. Some of these are open source, whilst others were commercially licenced from their producers.

The Independent JPEG Group are acknowledged on the About screen, where the Sonic logo also appears. Some of the open source programs and libraries are listed on the requirements page, though as of July 2006, the links to the actual acknowledgements and licence conditions are broken, which may mean Google is in breach of those licence conditions.

The Linux version of Picasa uses additional pieces of software, in particular it is based around Wine (an implementation of the Windows API on Linux), which itself uses gPhoto for its digital camera support; and Gecko from The Mozilla Foundation. There were a number of patches to Wine needed to get Picasa running on Linux.

Picasa release versions

1.0 - October 2002

details
Original program produced by Lifescape Solutions, priced at $30. Offered discovery of images on the computer, and some search features.

1.5 - Jan 2003

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Added more supported image formats, keywords, and cropping of images. A free upgrade from version 1.0

1.618 - July 2004

First free download version, after the company was bought by Google.

2.0 - Jan 2005

details
Major update, offering many new and improved features including: collage maker, screensaver, better search, more editing.

2.1 - Sept 2005

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Additions and inprovements included multiple interface languages, integration with Blogger, printing CD covers, RAW file handling.

2.2 - Jan 2006

details
More languages supported, bug fixes to CD writing, IE7 support, network drive support.

2.2 Joga Special Edition - June 2006

details
A branded version of Picasa, which offers upload support to the Joga.com football supporters website.

2.5 (beta) - June 2006

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Beta version, with many exciting new features, only available in association with a Picasa Web Album online photo album.

Export Templates

One of the few officially documented parts of Picasa is the Picasa Web Templating System, which has detailed documentation available as part of the installed files that come with Picasa. This will typically be at c:\Program Files\Picasa2\web\documentation\index.html

The Overview contained in that file states:
When the user does a web page export from the current album in Picasa, the Picasa Web Templating system is used to produce the desired HTML output. Web templates may be either template command (.tpl) files, or files which contain HTML formatting and special templating-system variables (typically with the extension .html)

During an export, thumbnail and large-sized copies of the selected images are written to the "thumbnail" and "image" subdirectories of the selected export directory, respectively. Then, the top-level template command file (always "index.tpl") in a template directory is processed and the commands executed in order. The special loop and targetloop commands are processed for each image in the selection, populating the special image loop and targetloop variables.
A number of developers have used this documentation to come up with export templates, that take data from Picasa, and produce it in another form.

Reviews

Articles and tutorials

Supported Image Types

Supported Video Types

Searching Picasa Web Albums

Searching Picasa Web Albums Google does not provide a search feature within Picasa web albums, nor does the normal Google search engine index the content of Picasa web albums.

The reason that the pages are not indexed is due to exclusion via the robots.txt file, which looks like this: 
User-agent: Googlebot
Allow: /$
Disallow: /

User-agent: *
Disallow: /
However, if a page that is indexed links to a Web Album, then the link itself is indexed, and the page can thus be found by the presence of the link. Searching for site:picasaweb.google.com will find all such pages. This search can of course be combined with other words to restrict the results to those whose link text or URL text contain that word.

On 12 July 2006, a search for site:picasaweb.google.com returned "about 18,800" results. (It's unlikely to be this high, since estimates are often very inaccurate), but changes in the number is at least indicative of how the number of albums known about is growing.

For comparison,Yahoo returns just 1 page (the home page).

Downloading from Picasa Web Albums.

downloadpwa Downloading from Picasa Web Albums. If the album owner allows it, Picasa Web Albums shows a link to "download album" on the album page. (This will only appear when you are signed in to Picasa). Clicking the link starts up Picasa (depending on your browser, and its security settings, you may get a warning popup indicatating this is about to happen), which then show you a preview of the items in the album, and allows you to confirm the download, or cancel it.

The files are downloaded to a folder on your hard drive, in a "Downloaded Albums" folder within your "My Pictures" folder. Within Picasa, the albums show up within the Downloaded Albums category of the left album list. Downloaded albums are further grouped by the name of the account they were downloaded from, and given the title they had on the web.

The mechanics of how the browser is able to start Picasa is that the link is of the form
picasa://downloadfeed/?url=http://picasaweb.google.com/lh/rssAlbum?uname%3Dname%26aid%3D1234567890
This unusual protocol has been registered as relating to the installed Picasa application, which the browser therefore knows to start to handle the link.

Command line usage

commandline Command line usage There are a number of command line functions that Picasa supports. Rather strangely, I have found that these are only recognized when the program is started using its full pathname of "c:\program files\picasa2\picasa2.exe". If you either miss out the pathname part of the command, or miss off the .exe, then the commands are not recognised. I assume that this behaviour is to discourage command line use - the command line interface is there primarily to provide for Windows Shell integration, and that always uses the full pathname form, so that is what is checked for.

Download from Picasa Web Albums

"c:\program files\picasa2\picasa2.exe" "picasa://downloadfeed/?url=http://picasaweb.google.com/lh/rssAlbum?uname={uname_value}&aid={aid_value}"
uname
the name of the user owning the web album
aid
the unique numeric id that identifies the album

Open a specific image in Picasa

"c:\program files\picasa2\picasa2.exe" "picasa://showimgtmp/?{numeric_value}"
numeric
the numeric id of the image to be opened
The numeric values of the ids can be derived from the the scanning database. Each relevant directory and file that is found during the scanning gets an entry in the database. A relevant file is one whose image type is recognized. A relevant directory is one containing a relevant file. (See dirscanner).

Passing a directory identifier as the numeric id in the showimgtmp command will have no effect.

Import a new button definition

Full syntax not determined 
picasa://importbutton/?url=

Upload to Google

Full syntax not determined 
picasa://uploadtogoogle/?

Open a specific image in Picasa

Full syntax not determined 
picasa://showimg/?
How this relates to the showimgtmp above is unknown. This version does not take the same numeric ids, but what it does take is unknown.

Data in the dirscanner database

dirscanner Data in the dirscanner database The dirscanner database holds a complete list of image files that the system knows about, together with the directories they are in, directories which should be ignored, and in the latest version, information on Picasa Web Albums.

Turning the dirscanner database into csv

The dirscanner database is normally stored, like the other Picasa databases, in a binary format.

However, if you change the registry setting HKEY_CURRENT_USER\Software\Google\Picasa\Picasa2\Preferences\WriteDirscannerCSV from a zero to a 1, then the file will be written out as a CSV (comma separated values) file, which can be more easily viewed.

The CSV file is written to c:\program file\Picasa2\db\dirscanner.csv

Viewing the CSV file

First action is to take a copy of the CSV file, and to always work on the copy - you dont want to run the risk of changing the original file, since its a vital database, and damage to it may well make Picasa unable to access your image files.

The file contains the following fields for each entry:
Name
the full pathname, including driver letter, of the resource. Directories include the trailing "\"
Creation Time
in days since 1st Jan 1900
Access Time
in days since 1st Jan 1900
Update Time
in days since 1st Jan 1900
Size
in bytes, zero for directories
Type
  • 0 - an unused database entry
  • 1 - a directory
  • 2 - a jpeg file
  • 3 - a gif file
  • 4
  • 5 - a directory which should be excluded from the scanning
  • 6 - a bitmap (.bmp) file
  • 7 - a psd file
  • 8 - an AVI video file
  • 9
  • 10 - an MPEG video file
  • 11 - a WMV video file
  • 12 - an asf video file
  • 13 - a tiff file
  • 14 - a png file
  • 15
  • 16
  • 17
  • 18 - a raw image file
  • 19 - a PAL file for a Picasa Web Album
Dirty
exact use undetermined
Valid
exact use undetermined
As a CSV file, it can be loaded into Excel for further consideration. There you can do things such as:
  • Find the largest and smallest files by sorting on the size column
  • Group all files of the same type together by sorting on the type column
  • Find the oldest files by sorting on the creation time
When loaded into Excel, the row numbers of the entries start from 2, since there is a row of headings along the top. This means that you need to subtract two from the row number, if you par using the file to get the correct image index numbers to pass via the command line 
"c:\program files\picasa2\picasa2.exe" "picasa://showimgtmp/?{numeric_value}"
(See commandline).