Either the frigates captain was lying, or the picture is BS, or both. The implications of any of these is an indication of the weakness of the British position, however.

The searched "ship" is described as a "dhow" in the early reports, and it looks rather difficult for the ship in the British picture to have been "acting suspiciously". It's big, known, and would have clearances. A dhow could act suspiciously, I would think.

"STEPHANIE KENNEDY: The 15 sailors and marines from HMS Cornwall were on a routine patrol in Iraqi waters.

"Commodore Nick Lambert is the commander of the frigate. Speaking from the ships decks he says they were searching a dhow, a traditional Arab cargo boat that was acting suspiciously.

"NICK LAMBERT: "The boarding party got on board. The ... it was entirely content with boarding. The skipper was quite content, he answered all the questions and the leader of the boarding party cleared him to continue with his business."

Types of dhow
Ghanjah - a large vessel with a curved stem and a sloping, ornately carved transom.
Baghlah - the traditional deep-sea dhow
Battil - featured long stems topped by large, club-shaped stem heads
Badan - a smaller vessel requiring a shallow draught