Pic via Ken Layne, who also has video posted. Along with some righteous words.
[Added] A partial screengrab from James Fallows's post, which is also well worth reading in its entirety:
More from Fallows:
This Occupy moment is not going to end any time soon. That is not just because of the underlying 99%-1% tensions but also because of police response of this sort -- and because there have been so many similar videos coming from cities across the country.
As a wise friend of mine predicted about a week ago.
The above is not a one-off. See, for example, Joshua Holland's report, "Caught on Camera: 10 Shockingly Violent Police Assaults on Occupy Protesters."
[Added2] In summary.