“A busy table this morning” sounds like an ordinary picture caption. Under a cropped image from a game publisher, however, it makes two surprisingly precise claims: somebody counted people, and somebody knows when they were there. A still picture of an interface may establish neither.
The public Teenpatti Master Online homepage provides a useful example. It labels its illustration as a preview of the game lobby and describes the Android app beside it. A caption such as “Lobby preview on the publisher’s Android app page” identifies both the subject and the source. Calling the same image a live online session would add something the original page does not establish. Even the date you saved the page only tells you when you saw the picture.
Cropping can change the way readers understand that distinction. Remove the label above the image and a preview can look like a screen captured by the reporter. Copy it into an article about browser access and a reader may assume it shows the browser edition. If you know only where the image appeared, say that. Keep a copy of the surrounding page for the person checking the caption, and confirm permission before republishing the image itself.
The visible caption and the image description have different jobs. A caption can name the publisher and say the picture is a preview. The alternative text should convey the part of the picture the article discusses. If that is a choice between games in a lobby, describe that choice. Repeating the brand name alone leaves a reader who cannot see the image with no idea what it was meant to show.