For Sunset Shimmer, letting a group of impressionable high school students in the know about another dimension where magic reigns and talking ponies are the norm is not the easiest thing to handle. It does not help that the portal to this dimension is right in front of the school.
Sooner or later, though, she has to deal with more than mere questions about Equestria. Twilight becomes curious enough that words won't cut it for her anymore. She wants to see this dimension for herself.
So, Sunset begins by offering to bring her camera through the portal to take pictures and videos of her next trip there in Equestria.