On 8 August 2016, political news site The Hill livestreamed a Hillary Clinton rally from St. Petersburg, Florida, issuing a tweet linking to the stream illustrated with what appeared to be a strange mock-up photograph of a crowd:
WATCH LIVE: Clinton holds Fla. rally after major Trump speech https://t.co/F6Po7rUF1i pic.twitter.com/Pg61mYcnlm
— The Hill (@thehill) August 8, 2016
However, Hillary Clinton's web site provided the rally's start time as 1:30 PM on 8 August 2016, so authentic images from the rally couldn't have been used to illustrate the tweet in question, which was posted prior to the event. So the photograph used in the tweet was one published by The Hill on 19 April 2016 as part of coverage of the New York state primary election.
Elements captured in the photograph (such as a podium, a big "H," and two American flags) were visible in video footage of Clinton's earlier New York state appearance
Other images from the event depicted a scene that somewhat differed from the photograph in question, but the rally in New York was certainly sizable: