Carol, there is no tablet on the market that meets your requirements, except possibly the new MS Surface, but an arm and a leg for a fully specified one (Apple sized prices), and you still have limited on board memory (64gb including OS and RAM), and you'll still want an e-ink reader (try reading a tablet in bright sunshine . . ). Reviews include sentences like 'now you can throw away your iPad and laptop'. Definitely an exaggeration !
It sounds like what you need it is a netbook (but buy soon, there are only two manufacturers still making them), or a budget laptop, both augmented with a wifi dongle, and a e-ink reader. I have a Kindle, but tend to agree with Don that a Kobo is a slightly better choice. Both less than £100 (€120).
I have a £100 7" Android tablet which has a micro SD expansion slot (I keep my videos, pictures and music on that), USB port and HDMI out. I occasionally use it to show pictures on, but with Elements light on it I wouldn't hesitate to say it's pretty useless for editing. Although Pixlr-o-matic can while away some dull time. And the battery only lasts about 5 hours, half that of an iPad, Galaxy or Nexus. It was designed to be used in the home, and so it is never far from a charger.
Not having any Apple products I don't know if Safari can do this or not, (Colin?). A major plus point of Android tablets is that they can run Opera Mobile (iPads claim to have this facility, but actually all you are getting is a cut down version wrapped up inside Safari). Opera Mobile is fast and has desktop emulation that makes the websites you are visiting think that they are talking to a linux desktop OS - so you get the whole site. Given that Flickr's mobile site is useless (and Facebook's is not much better), having access to the full site on a tablet or 'phone is rather handy.
As Colin says, you can pay through the nose to get a 64gb iPad with 3G, and then pay more for apps and connectors, leaving the cost not much shy of £700. And it's still poor for reading books. And personally I hate typing on a screen.
Looks like you have hours of umming and aahing ahead of you. Can't say I envy you on this one.