Image quality – Guide for iPhone 6 and iOS 8 Review

Why do pictures on Instagram and tumblr look like they were taken with a low quality phone or low pixel camera? I had the iPhone 5 and after the ios7 update it started doing that. I now have the iPhone 5s and it's doing the same, how can I fix this?
Review by #1Superstarjoe on Guide for iPhone 6 and iOS 8.