It was a stunning accusation of disloyalty, but the substance has all but been lost in the hoopla around the body language between the two of them, and the gender imbalance in the room. (For the record, a handful of other women were in attendance, including Representative Liz Cheney, the No. 3 House Republican, who is partly obscured by Ms. Pelosi’s outstretched arm as she points to a glowering Mr. Trump.)

During the meeting, the president had insulted Ms. Pelosi, calling her a “third-grade politician” (at least that was her account; the White House later insisted he had said “third-rate”) and reacted with an angry taunt when she turned to leave, saying, “Goodbye, see you at the polls!”

Hours before he posted the photo, Ms. Pelosi had returned to the Capitol and told the news media, “Now, we have to pray for his health, because this was a very serious meltdown on the part of the president.”

Mr. Trump used the photo instead to hurl the very same accusation back at Ms. Pelosi, as he often does when he is criticized, and his fellow Republicans pointed to the image as evidence that Ms. Pelosi was being disrespectful to the president. But Democrats saw something else: a powerful woman schooling an impetuous man, or perhaps a mother scolding a toddler — not to mention a fund-raising opportunity.

A group called Mad Dog PAC, which describes itself as a “high-impact, high-visibility, nonviolent activities to help bring about the impeachment and removal of Donald Trump,” is now selling coffee mugs bearing the picture. “Celebrate Speaker Pelosi bringing it to the toddler in chief with our new Pelosi Owns Trump ceramic coffee mug,” its website declares.