The multiple uploads feature[1] would allow a user to select multiple images from his gallery, enter a unique title, description and categories and upload them to commons. 

Considering one would end up uploading anywhere from 3 to 30 images, we have been iterating over a two views[2] that could best allow the user to perform these operations. 

Option A - shows only a single image to the user and gets the user to swipe between images. this keeps the user in the context of the image, something that is crucial while describing the image.

Option B - Shows multiple images in a single screen. the user can tap the image to see it better. 

categories and description get copied across images and the user is free to edit them. 

feedback and comments welcomed :)  

[1]http://upload.wikimedia.org/wikipedia/commons/6/64/Multiple-upload.png
[2]http://upload.wikimedia.org/wikipedia/commons/f/ff/Multiple-uploads-1-2.png