Boris Johnson stares into the distance, his brow furrowed, a lamp softly illuminating his features and a document in front of him. The image is pensive, deliberate and staged, and somewhat unusual as political portraits go. After all, most politicians don’t sit for resignation photos.

Mr. Johnson, who stepped down as Britain’s foreign secretary on Monday, has come under criticism for a series of portraits taken the day of his resignation, one of which appeared on the front page of The Daily Telegraph on Tuesday. The pictures show Mr. Johnson sitting at a desk with a pen and copy of his resignation letter at the official residence of the foreign secretary.

The flamboyant politician’s departure came in protest of Prime Minister Theresa May’s moderate approach to Britain’s withdrawal from the European Union, known as Brexit, and has deepened the crisis facing her government. Mr. Johnson’s political opponents quickly seized on the pictures as evidence of self-interest.