Your demo can't work on devices that do not use /images/DCMI as an image folder. And your buttons are so small on my device that I can hardly read their text.
I hesitate to test your demo with my camera folder. Does your library can change its content (removing, adding...) ?
EDIT: I tried to load pictures and I don't know if it's a problem with my device (Huawei Honor) or Android version (2.3.6), but the horizontal scrolling is so choppy that's horrible to use.