There is a quick update on picasa plugin.
If you want multiple users, in the picasa username field, separate users by semicolons ( ; ). You can use the album names inside brackets infront of the username. Separate album names by commas ( , ).
Example : sandaruwang(Adams Peak, IOI 2006);yasaruwan(sivali)
Edit : Latest update http://www.sandaru1.com/2008/04/04/wordpress-picasa-plugin/
I just updated the picasa widget. Thanks for the comments on the early version. Now, you can select the image size. Then, picasa username field get bit complicated.
If you want to use your whole picasa album you can just type your username. If you want only one album then you can put the album name within brackets(Without spaces). Here is an example : username(album).
If you want to get photos from more than one user, then type all usernames separated by space. You can even use brackets with the usernames.
When I saw cool random photo display gadget at wela’s blog, I also wanted something like that. Earlier I had a gallery2 installed, but when Google released picasa, I found it much easier. It actually optimizes the photos and then uploads. So, I switched to picasa. Fortunately, picasa have RSS feeds for each album 
.
At first I thought of writing a normal wordpress plugin, but then since it’s in the sidebar, I thought of writing a widget. My blog was running wordpress 2.1 and either I had to install the widget plugin or install the new wordpress 2.2(Wordpress 2.2 comes with the builtin support for widgets). Since there are some bug fixes in version 2.2, I upgraded to that.
Then, after coping about three lines of codes into my theme, I widgetized it. Then, finally it’s writing the widget.
Actually, the widget was fairly easy to write because the wordpress itself has a rss parser. Even though, it doesn’t completely parse the RSS given by picasa, I managed to use some regular expressions and get the necessary values.
When I finished writing the widget, I realized that there is no point of downloading the RSS each time when someone requests the site. So, I put a download delay time and the stored the parsed RSS results as a wordpress option.
If you want to try this, click here to download. Copy the file into wp-content/plugins/widgets directory. Then, activate the plugin and add that to the sidebar from Presentation -> widgets. (You should have widgets plugin installed)
