If you develop apps, most probably you will want a user to load up his/her own photo into the app. You can test the UIImagePickerController function by testing loading a photo from either the "Saved Photos" folder or "Photo Library" folder inside the Photos App. But often, after a new installation, both folders are empty.
To save the photos to Saved Photos album, you can just drag any images onto the iPhone simulator whereby it will opened automatically with Safari. Then you can click and hold on the image and an ActionSheet will slide up and you can save it. Images saved in this way are copied to the Saved Photos album. How about Photos Library folder? See below:
There are 2 ways:
1. To populate the folder Saved Photos: Copy and paste photos to this folder (if not exist, create it by yourself):
[USER]/Library/Application Support/iPhone Simulator/User/Media/DCIM/100Apple/...
2. To populate the folder Photo Library (if not exist, create it by yourself):
[USER]/Library/Application Support/iPhone Simulator/User/Media/Photos/...