Have you got both facebook and flickr enabled through pipepixel? ... and did you set both accounts to upload by default? ... you can disable flickr in the pixelpipe settings (on their website) simply by hitting remove default or something similar ... then they'll only go to flickr if you add @flickr to the title or text ... it really does sound like you're overloading your wifi ... can't think of another reason it would stop half way through ...