Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
Ida Lupino and Glen Ford star in this Western adventure but they have nothing to do with the two rattlesnake scenes.
Early in the movie we see Barry Storm, the grandson of "Dutch" Walz whose legendary "Lost Dutchman" gold mine is reported to be hidden somewhere in the Superstition Mountains in Arizona east of Phoenix. Barry is hiking through the mountains hoping to find the treasure like so many before him. He sets his foot down right next to a rattlesnake that strikes out and puts two fang holes in his pants but misses his leg. (This shows why it's wise to wear something thick that covers your legs in rattlesnake territory.) The rattlesnake then crawls toward Barry, but like almost everybody in movies, Barry is too ignorant to know that he can get up and walk faster than a rattlesnake can crawl so instead of moving away from the snake he throws rocks at it until he kills it. (The live snake was poked on the head by an object that is not possible to identify. It looks stunned but was probably not harmed.) This rattlesnake encounter appears in the movie not to prove Barry's bravery, as it would in most movies, it's here only as an excuse for him to find a clue. After he picked up some rocks to throw at the snake Barry notices that he uncovered an old gun that might be a clue that he's close to the lost gold mine.
The second rattlesnake appearance is less believable. It helps to determine the outcome of a fight. Near the end of the movie there is a climactic fight between Barry and a Sheriff's deputy who has also been searching for the mine and has killed more than twenty men because of it. After considerable fighting at the edge of some cliffs, Barry falls and hangs on by his hands (a literal cliffhanger). The deputy climbs around a rock to kick Barry off the cliff, not knowing that right behind him on the rock at neck level there just happens to be a conveniently-placed rattlesnake. The snake strikes him on the neck two times causing him to lose his balance and fall off the cliff, an appropriate ending for such a bad guy.
The first snake we see is a fake snake that is rigged to make it strike out forward then spring back. Next we see a shot of a live rattlesnake, either a dark Western Diamond-backed Rattlesnake or an Arizona Black Rattlesnake crawling to the right of the frame. The second rattlesnake we see at the end is another fake rigged to strike - probably the same one used in the first snake scene.