This is a picture of the Nazi flag with a swastika that represents the power of Nazi Germany. This relates to the novel when Rosa and Hans are worried that they will not find their flag to hang up outside their house to celebrate Hitler's birthday. They end up finding just in time before the Nazis could question the Hubermanns.
The Aryan Brotherhood, also known as The Brand, the AB, or the One-Two, is a white prison gang and organized crime syndicate in the United States with about 15,000 members in and out of prison. According to the Federal Bureau of Investigation (FBI), although the gang makes up less than 1% of the prison population, it is responsible for up to 18% of murders in the federal prison system.
Good Grief… Former Justice of Peace Arrested for Texas Murders – Not Aryan Brotherhood Members http://www.thegatewaypundit.com/2013/04/good-grief-former-justice-of-peace-arrested-for-texas-murders-not-aryan-brotherhood-members/