The “Cobbe” portrait of Shakespeare, named for the family estate where the painting was found, not for the artist (who remains unknown), stands on good evidence to be the only portrait of the Bard actually painted from life.
The painting has crossed the Atlantic and is currently on display in New Amsterdam, er… I mean New York, at the Morgan Library and Museum.
Accompanied by a few other Shakespeare portraits (like all other known portraits, created posthumously), the Morgan’s first folio 1623 edition of Shakespeare’s plays and other related artifacts, the painting will be on display through May 1, 2011.
Unfortunately, the Morgan hasn’t seen fit to put more than a small image on their site.
I found large images of the painting here, accompanying a post on Doobybrain, and here accompanying a post on Fragments. The latter image, though smaller, looks to have truer color.
For more on this portrait and a comparison to other key portraits of Shakespeare, see my post: Shakespeare’s Portrait? from March, 2009.