Yes, in most cases the hotel photos and descriptions come with the connection, so you are not left building a hotel library by hand. Alongside the live availability and pricing feed, hotel suppliers normally publish a content feed that carries the hotel name, the address, the location on a map, the star rating, a written description of the property, the facilities list and a set of images. Your portal reads from that content, so when a customer opens a hotel page they see pictures and a description without you typing anything in.
How good that content is does depend entirely on the supplier, and it varies more than people expect. Some suppliers send a generous set of large, recent images for every property, while others send only a handful, or images that are small or clearly dated. Descriptions are often available in English only, and the facilities list can be thin for smaller independent hotels. If you connect more than one supplier, the same hotel may arrive with different photos and wording from each, and the portal has to pick one version to show.
For hotels you know well, particularly ones you contract directly or sell heavily, you can usually upload your own images and write your own description so that property looks exactly how you want it. That is worth doing for your top sellers rather than for every hotel in your range, since the supplier content is generally fine for the long tail.
Before you go live, ask us to show you hotel pages for two or three destinations you actually sell, so you can judge the photo quality for yourself and decide which properties deserve your own content.