Adding photos to your hubs engages the reader more, draws their eye and makes your hubs more user-friendly. Likewise, adding links (either on sidebar or directly into certain words in your capsules) gives the reader more information on your subject matter and a gateway to new places to investigate.
awordlover used pictures -photos, paintings and clipart- on all her hubs (sometimes overmuch) and recently the team has been going over her older hubs because Hubpages' rules have changed regarding usage, source and links. Because many of her earlier hubs have no links to where she located the photo, we have to delete those photos because the copyright ownership is questionable. We are now revamping those hubs with updated photos, source links etc. In doing so, we are seeing a large amount of hub views of the revamped hubs. So this proves that photos are an important part of creating your hubs.
Use photos, videos and links wherever possible and every month or so, go back and check your links to make sure they are still linked to a published work (not a dead end). Good luck in your writing.
Jillian Burns, a member of awordlover's team