In the last cohort we had a discussion on this topic: How to link the image used for tribute page on my desktop
I think the discussion page kept going from the last cohort so you should all be able to read those too?
I hosted images on github, which took a bit to figure out. For my projects, I sourced free images from unsplash, and attributed the artists/photographers in my footer section. At first, I used the cat photo as a placeholder and worried about getting the code right, and later got all my images working. Hope that helps!