Hello, all in a sudden I am not able to rotate the pictures and videos from album. I notice that there is a lock on the upper right, but I can't recall how I enable and disable it. Does anyone know how to fix it ?

Double click the home button to reveal the multitask bar, scroll to the left inside the multitask bar, you will see that icon there, touch it to desable rotation, touch it again to enable rotation whenever you want your screen to rotate again. Press home button once to close multitask bar.
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