Just a tidbit of information here.
There's a rather useful resizing app with crappy reviews, because the concept isn't understood. An iPhone displays a photo in your album to fit the resolution of the screen, no matter what, so it has like 2 1/2 stars because people are dunces.
Anyways, just search resizing photos in the app store and it comes up. App name is just "resize photo." Then you can upload to whatever the hell you want. I personally strted using imgur, but whatever.