On Android 4 ICS (and possibly others), a giant thumbnail file may be created in your DCIM folder. This file can be several Gigabytes in size, depending on how many pictures you have. It is generated by the Android Gallery app. Here's a list of different ways to prevent or reduce the size of that giant thumbnail file. Quick and temporary solution- just delete any files/folders in your DCIM folder that start with .thumbnail Create a file named .nomedia in certain folders to prevent the gallery from scanning those folders. More info Delete the .thumbnail and replace is with an empty folder or empty file. More info A thumbnail deleter app developed by ppero196 I personally use option #3. Works good for me.