Basically it would allow people to upload images of rides or their machines. You could upload those images into the gallery and then post them on the site. Kinda like people go to Photo Bucket and upload their images and then link them in their posts. Instead of them being hosted elsewhere, they would be stored locally.
We could also store small videos as well (but you tube is usually a lot better for that)
The other thing is some people while at work are behind firewalls that block image hosting sites, therefore, if you post an image from that site, that user behind the firewall would be unable to see it.