just looking at Adobe Stock & wanted to confirm that the measurements are in Pixels ?
There is nothing to tell you and i'm looking like it seems to big to be any other unit but just want to confirm.
Adobe Stock contains, photos, illustrations and vectors. So, if you are downloading photos, they will be in jpeg format and will be in pixels only. However, if you download illustrations and vectors, they will be in .ai, .eps and .svg formats.
Hope that answers your questions.