This is "the flag of al-Qaeda in Iraq" (AQI). Please be sure to read the below description before considering including this image in any Wikipedia articles.
This image shows a design for the w:jihadist black flag based on flags used by w:Jama'at al-Tawhid wal-Jihad (JTJ) in Iraq during 2003-2004.
The design uses the basic jihadist black flag.with the shahada inscribed in white, and adds a white or yellow circle surrounded by additional text. These flags were seen in various beheading videos published by terrorists in 2004, e.g. here, where the circle is surrounded by the text Jama'at al-Tawhid wal-Jihad in yellow.
See en:File:JackHensley.PNG.
No flag with the design shown here has been spotted. The flags attested in videos in 2004 have the text Jama'at al-Tawhid wal-Jihad surrounding the circle. The circle does not occur on its own. Also, this design including the circle is limited to the years 2003 and 2004. We have no evidence that it has been used either before or after that period, or outside of the Iraqi insurgence of that time.
The "disk" design apeears to have been peculiar to the JTJ in 2004.
2004 videos by Jamaat Ansar al-Sunna show the same black flag with white shahada plus their group name but without the disk.
The report is by one "Colonel Emerson Begolly" and reads as follows:

"It is the new al-Qaeda flag, black with the 'long version' of the Shahada in a yellowish colour and a yellowish circle in the center. I have seen the flag several times before before; I was in Iraq for the past 6 months. The flag is being debated as either Abu Mousab al-Zarqawi’s al-Qaeda (Ansar al-Zarqawi) flag or the al-Qaeda flag in Iraq. I never act[ua]lly saw one flying, etc. This flag was used in the back[g]round of several beheading videos. I was given, and still have, a captured flag like this one from another soldier who raided an abandoned al-Qaeda safe-house in Fullujah. The flag was not a machine-produced flag, but two pieces of black nylon with embroidered lettering and the circle in a light yellow. It was not made to fly, but rather to hang on a wall. I know another soldier who has a flag like that one, but only the lettering and circle is white, not yellow like the other one. The videos are not clear enough to tell whether the lettering and circle is white or yellow, but it probably differs depending on who made the particular flag."Note that this report is simply what had been posted online back in 2004, there is no kind of verification attached to it. Also note that Emerson Begolly is the name of a "Nazi buff turned Jihadi" arrested in January 2011.[1][2][3]
This Emerson Begolly was aged 21 in January 2011, and thus was about 14 in Sept 2004.
He had been active in jihadi online fora under the name "Asadullah Shishani" since 2009. 
Before that, he was apparently into posing as a Nazi in earlier years. 

The coincidence of the name "Emerson Begolly" and the interest in Islamist terrorism etc. is enough to arouse suspicion in the report cited above, unless it can be verified that there is indeed a bona fide Colonel Emerson Begolly unrelated to the "Nazi Jihadist" online activist. --Dbachmann (talk) 16:09, 6 May 2011 (UTC)
History of this file:

Originally uploaded by User:Lexicon as Image:Flag of al-Qaeda.svg.
The source for this design is a report from 14 September 2004 published on the Flags of the World Website[4].
Emerson Begolly