Re: viewing photos inside the post
The allow images plugin is the one you need (the attachments one just allows attachments to posts).
Did you activate it?
People will need to have the image posted somewhere before they can insert it into their post. It can be a flickr URL, Photobucket, ImageShack, Picasa, whatever, so long as the image is publicly available on the Internet. Once the image is accessible on the Internet, they just need to insert the HTML to embed the image. the img tag will look like this:
<img src="http://www.flickr.com/whatever.jpg" />
If you post a URL to your forum, someone can try it to see what’s happening.