Billionaire Warren Buffett is auctioning off a high-tech signed portrait of himself to raise money for one of his favorite charities, and the bidding has already topped $30,000. The portrait of Buffett features a grid of letters over the picture that light up to spell out several of the legendary investor’s famous quotes. The eBay auction of this artwork probably won't rival the $19 million someone paid earlier this year for a private lunch with Buffett, but it’s still likely to attract big bidders before it wraps up on Buffett’s 92nd birthday on Aug. 30. The proceeds from the art auction will go to Girls Inc. of Omaha, which provides educational, cultural and recreational programs for young women in Buffett’s hometown.