Model # SM-N900T
Android Ver. 4.3
Kernel Ver. 3.4.0-1670611
Pictures taken with the phone camera (either on onto the device or onto the SD card), that were never moved off the device are recognized by any and all media apps (such as Gallery) as pictures and, therefore show up normally in the media apps and can be manipulated there (rotating or cropping, for example).
Recently and without anything being done, I noticed that all pictures that were uploaded from a computer onto the phone have disappeared from the media apps. That included pictures that I originally took with that phone then moved onto a computer and then moved back onto that same phone, as well as the pictures that I just moved from a computer that had no relation to the phone's camera to begin with. All of those images are of *.jpg format. The file managing apps (such as My Files) do see those files and are sending to open them with my default picture app (Gallery), which opens them but does not give me any options as to edit or anything else.
Tried to drag-n-drop in a dual window mode from My Files picture opened into a new folder into Gallery - the result was a message "file not supported".
This is just weird.
What could be causing this and how do I correct this? Any help would be greatly appreciated!