I don't like the idea that Google employees can view my private pictures. Is there a good app to encrypt and store all my photos in Dropbox or Google Drive?
Boxcryptor protects your files in the cloud no matter if you use Dropbox, Google Drive, Microsoft OneDrive, SugarSync, Box.net, or any other major cloud storage provider. It also supports all the clouds that use the WebDAV standard such as Cubby, Strato HiDrive, and ownCloud.
Boxcryptor have free/paid versions.It works on all major platforms including computers/mobiles, just see the download for more details
In regards of security, Nordlocker is a good solution for file encryption with high privacy focus as well. It protects files with easy encryption process (drag and drop into the locker). Only you and people with password can access them.
It has a free option, which allows to encrypt up to 5gb of data for free. I started from this version three months ago and I sticked to it (now I pay less than 3 $ monthly). A straightforward interface makes it very easy to know how to setup and use it. Worth every penny.
Actually, I'm satisfied with the feature to keep files on my computer, however, application is compatible with any cloud storage provider.