Can I create a webpage with envato pics for an affiliated agency that will sell it to their client.

A befriended IT Agency ask me to produce a web design for their client. I want to use pictures of my envato elements subscription for this web design. Since the web design is for their client I’m not sure if I can use Envato Elements for this purpose.

You could do but under the elements license e.g. you need to be subscribed when you finish the project for them and you cannot distribute the source files/assets to be reused in a different or modified design after you unsubscribe