All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If these movies are permissible to watch, then the ruling regarding the permissibility or prohibition of watching them depends on the terms and conditions of the site itself, and one should deal with them according to the permission of their owners whose rights must be reserved and whose conditions must be fulfilled, there is no doubt that they gave permission to benefit from these movies according to their conditions.
However, if these movies are forbidden to watch, then whether or not the site gave permission to download them, it is forbidden for you to watch them; for more benefit, please refer to Fataawa 89099 and 84494.
Allaah Knows best.