For Joomla 1.5, 2.5 and 3x.
We have a FREE version and there are Pro version.
* Easy to install and use
* Choose your own thumbnail size
* Config maximum pictures per page
* Config how many picture in a row
* Multiple web albums on one site
* Very fast light-box tool to show pictures
* Automatically updated when changing picasa
* Reduce costs for hosting!
07-10-2014 >> There is a new version available, for Joomla 3.0
Tho its a component it works more like a plugin. It has no backend but parameters can be set when creating menu links.