Tapatalk will post your photos full size. Go to your App Store and download the free app. Search for Eastman's Forum and connect with it.
Find the thread you want to post to, click on that thread, then at the bottom of the screen you will see Write a reply, click there, then you will see a + just to the left, click the plus sign, then you can write what you want. You will see a square box at the bottom of the screen to the right of the camera icon, it's a box with a little mountain, click that, add your photos and when asked click Best quality then the photo will be attached. Hit reply at the top right and your done.
You can attach 4 photos to each reply.
It sounds like a lot but once you've done it a time or two to goes real fast and the photos are full screen and great quality.