I have a Nexus 4 and I can't find my photos or my customized ringtones anywhere. Help!

[AC Question]

As of two days ago, all of my photos and customized ringtones disappeared from my phone. I was about to upload a photo to Facebook through the Facebook app. When I trapped the icon to upload a photo it opened the Photos app and everything was there. But just as I was about to select my photo, the screen flickered and all my photos disappeared. I tried turning my phone off and back on (thinking it has glitched), but they were (and still are) gone. I went into settings to see the storage and it says that I have 2.5GB with of photos and videos on my phone, but they are no where to be found. However, when I hook up my phone to my computer there is a DCIM folder that has all of my photos and videos, but I can only view this folder from my computer. Whenever I take new pictures, they won't store in the photos app; they keep going to this folder. Why did this happen and how do I fix this? Also, after the screen flicker all my customized ringtones disappeared as well. I noticed this because when someone called me my ringtone was different. When I went to change it back, they were no where to be found. Help, please!