Head to the photos tab
In the Facebook mobile app, go to your profile and head to the "Photos" tab. Then select the album where you'd like to upload the photo.
Find the camera icon
Tap the camera icon in the upper right of the album view.
Choose your photo
Tap the camera button and choose to take a snapshot, or choose an existing photo from your library.
Caption and upload
Once you've chosen the photo, give it a clever caption and hit "Upload."
Your newly uploaded photo will be placed in the specific album you chose instead of "Mobile Uploads."