Reuters photographer Leah Millis was covering a rally for then-President Donald Trump on Jan. 6, 2021 when she received a text from her colleague Tom Brenner at 1:06 p.m.Four chaotic hours later, she captured the exact moment a flash-bang grenade, fired by law enforcement to disperse protesters, illuminated the Capitol steps, throwing tear-gas smoke into sharp relief and casting a shadow of the American flag onto the iconic dome. The image reverberated across the United States and abroad in 2021. Media outlets and Congress have used it to emphasize the gravity of the day and to illustrate a symbol of...