Can I use my custom icon with Google +1 or am I obligated to use one of the icons provided by Google? If I can, how?
Thank.
I don’t think you can, as API +1 is not publicly available (at the time of this writing).
However, you can configure this button:
http://www.google.com/webmasters/+1/button/
Alternatively, you can try to figure out a +1 script and see if you can hack something:
https://apis.google.com/js/plusone.js
, Google +1. https://developers.google.com/+/branding-guidelines#plusone-button