Answer:
Longer
Step-by-step explanation:
In order to form an imagination, people will utilized pieces of our memory that we stored in our brain in order to create the depiction or scene that exist in our imagination. These pieces of memory came from the things that we observe with our senses (such as the pictures that we look, the shape that we felt with our skin, etc)
Imagining something that has longer / elaborate movements tend to utilize more pieces of our memory. This is why the process tend to be longer compared to imagining scene with short/simple movements.