I think Junior Member / Member, basically depends on the amount of posts you have made?
Don't think it will restrict you from posting pictures... if you mean using tag. Well it's off everyone right now.... you can see at the bottom of the forum that it's off. You can however attach pictures. I suggest attaching small pictures, I believe these are uploaded to the Forum server and eat up bandwidth = $$$
And as far as signatures go, those will show, as long as you have them on your own server/webspace.
The member status only has to do with your post count, it has no effect on your ability to use bulletin board features. Right now certain features are turned off and are not available to anyone. One of these features is the ability to post pics using the "img" tag.