Can no longer attach pictures to messages from 'gallery' on Samsung Galaxy Ace 4
I had a similar problem where when I tried to attach an image, it went straight to my Google Drive, instead of giving me the option to choose Photos, Gallery, or Drive.   

In my case Drive had somehow become set as the default.  I went into Settings --> Application Manger --? Drive and hit the button to remove it as a default applications, and that took care of it.