I can no longer post pictures
Before we can help you, could you please supply a few more details? Like which device you’re using the Twitter app on, and you’re using the most recent version yeah?
One method - without knowing what device you’re on that may work, fully close the app and open it back up again, so don’t hide it/keep it running in the background, actually close it (iOS: double click home button and slide up | Can’t remember what it was for Android though) and then try again.
first I am using an I phone 6 + and the app is allowing me to take a pic and upload it, but it won’t let me take from my photo library. What could it be?
Have you granted Twitter access to your “Photos” on your iPhone?
(iPhone) Settings -> Twitter -> Photos