Pictures do not appear at the gallery?
Clear app data of Media Storage app.
Find and delete .nomedia files on sdcard.
And reboot.


Terminal command to delete .nomedia files recursively.
Install Terminal Emulator for Android app. Open it and enter the command.

find $EXTERNAL_STORAGE $SECONDARY_STORAGE -iname ".nomedia" -exec rm {} \;

NOTE: Since android 5.0 doesn't allow third party apps to delete contents of external sdcard, U may need root permissions before that command to delete any .nomedia files on external sdcard. In terminal emulator, Hit su and enter and grant root permissions before using that command.