Components
I have suggested some features about the appearance of the pic and added some features to it that will make it easy to use and gives security to the data in it.
Proposal
The following modifications should be done to it to make it more attractive and trustworthy app.
- Addition of profile pic in the beginning of the app. This would make it more presentable.
*add an option of Trash bin in options. So that the pics that were deleted recently could be backed up.
- pinch zoom is not applicable on folders. If this option is added to it, user can adjust the folder size according to his convinience. Which would also over come the burden of choosing number of rows and columns. Pinch zoom would make it totally easy to do it.
Before pinch zoom, the folders look like this.
After pinch zoom. The folder view is as:
The presentation of these folders is applicable in vice-versa also.
*The details of the options that we choose in this app should be also written below the option. E.g see the difference.
*The hidden photos of the app should not be made easily accessible. Once u hide pics there should be no folder (hidden photos) in the options of app, rather there should a secret option of drag down the folders to review the hidden photos. After that the lock or password should appear to view them. Let me show u how. 
See by dragging down the folders upto the middle of screen, lock appears in which the hidden folded are available. This feature would make this an exclusive app to have it and provide the more security to photos.
*also there is no provision of sign in or link with Google account. That should be available. 
Benefits
After adding these features I think the appearance will enhance and the security of the data kept in app will increase.
Posted on Utopian.io - Rewarding Open Source Contributors