Hello,
For what you are looking for, it would be a better option to use an image gallery plugin that allows uploading images to registered users. It is not convenient to allow anonymous users to upload images as there would be a very high risk that the gallery would be flooded with spam.
A good option would be to use the Phoca Gallery component:
The following link talks about its configuration to allow uploading images from the front of the web:
Answered : 06/02/2014 3:41 pm