Answer:
The text and the film have these two themes in common: the danger of jumping to conclusions when you don’t have all the evidence and the idea that crime never pays.
The first theme is developed with the appearance of the gypsies. The film opens with gypsies drinking and celebrating on the manor grounds. So right from the beginning, the director puts the spotlight on the gypsies. The original text also contains details about the gypsies and their unconventional behavior. As a result, both in the text and in the film, Holmes (along with the audience) begins to suspect that the gypsies may have had a hand in the murder of Helen’s sister. Holmes’s jumping to this conclusion leads him away from the true criminal.
Both the text and the film also portray the theme that crime backfires on the criminal. In both versions, the snake that Roylott plants to carry out his killings ends up killing him. I think the film and the original text both do an equally good job of presenting these two themes, but seeing the film really makes those themes come to life.