The movie is quiet until an animal crosses the screen. Your dog charges toward it, barking at a picture that cannot possibly answer back. To them, the movement or sound may still be startling or exciting. You do not need to decide whether they think the animal is "real" to make movie night easier.
Start by preventing the loudest repetitions. Choose a different program, lower the volume, or let your dog relax in another room with something safe to chew. Keep them away from a television they might knock over or damage. If they are tense, panting, or unable to settle, give them more distance rather than asking them to stay next to the screen.
Practice with the easiest version
At another time, play a short, quiet clip featuring a dog while your dog is far enough away to remain comfortable. Offer treats as soon as they notice the screen, before a barking burst begins. Pause the clip and let things settle. If they bark or run forward, lower the volume, shrink the picture, move farther away, or use a less exciting clip. Only one change at a time makes it easier to see what helps.
Teach a simple alternative, such as looking at you or resting on a mat, away from the television first. Then reward it during easy clips. You don't need to keep playing the clip until your dog stops barking, repeated loud exposure can be too much, especially if they seem afraid. Short, comfortable practice beats a full episode of distress.
Some dogs remain relaxed around most programs but react to a particular sound, such as a bark or a doorbell. Write down which moments trigger the response and adjust your practice accordingly. If your dog becomes aggressive, highly distressed, or starts reacting to ordinary sounds around the home too, ask your veterinarian and a qualified, reward-based behavior professional for help.
Movie night may end with your dog sleeping in the next room. That counts as a good plan, not a failed lesson. If fast motion on screen is the trigger, the movement and chasing guide may help you think through the response. Keep the television secure and let your dog watch something else.
Sources: American Kennel Club: How Do I Stop My Dog From Barking at the TV?. VCA Animal Hospitals: Can dogs see movement on TV?.