You can post from your own files, but the size is very limited. Photobucket, Flickr, etc allow you to use full size pictures.
I have been using Photobucket and Flickr for years now with no problem. I would much rather have the photos hosted else where just in case they do have a virus on them, it doesn't affect our forum.
But the option is there where you can add photos, when you post a topic, click on "Additional Options". There you will see the option for attaching photos..