I am looking to put some photos on the net, so have been looking at photo
sharing sites like PBase.com.

Out of the ones I have looked at, I like PBase the most, but I want the
large version of each photo to be more than 800 pixels per side (in fact
more like 1280 pixels). I would also like the large version to open in a
standalone page (so basically all that is on the page is the actual photo
itself).

Any suggestions, apart from creating my own website?