||QR Image plugin is using Google Charts API for generating QR codes from specified URL.
Generated QR Codes are saved in a folder for better caching and less URL requests from other domains.
Optionally you can also use base64 encoded images (watch out for IE family in this case).
Since Version 1.3 you are able to generate QR Code containing not only URL but also text, vCard, meCard, Telephone or Email information.
With action='custom' you are also able to use it in combination with other Plugins or UDT's for example vcard Plugin http://dev.cmsmadesimple.org/projects/vcard.
For more Information please read Help text.