The uploading of pictures and images is restricted to users with either Admin or Content-Admin privileges.
To upload photos, go to the Expanded Menu by tapping the menu icon at the top left of the screen. If you have the requisite rights to upload images, you will see the menu item 'Upload Photo To Gallery'. Tap here and then 'Select Image'. You'll be asked which Album you would like to upload to and you can either select an existing album or choose to create a new one.
Once you've decided which Album to use, you will be able to choose which image to upload. Once you've chosen, your image will be displayed on the screen. Now just tap on 'Upload Image' and you're done.