Due to the cost of bandwidth it wasn't economical for us to host user's pictures any more... so you'll need to host them somewhere else, and then you can link them into your posting here.
I'd suggest flickr.com for the sheer reliability and spread of functions they have (you can even edit photos to some extent online.)
Otherwise, imgur.com is a real quick and easy way to host images. You don't even need to sign up for an account.
Once you've uploaded your image, you need to find the address for the image.
In flickr, go to the photo page in your photostream, click Share This, select "Grab the HTML", change the selection box to BBCode (which is what our forum runs on) and copy the code it gives you. Then just paste that into your post.
The code looks like:
[url=https://flic.kr/p/gUoSYo][img]https://c2.staticflickr.com/8/7397/10438273246_1685ed3e9f_z.jpg[/img][/url][url=https://flic.kr/p/gUoSYo]Untitled[/url] by [url=https://www.flickr.com/photos/savidge/]hir0[/url], on Flickr
and the end-effect is like:
Untitled by hir0, on Flickr
In imgur as soon as you upload it you get a page with all the link options on it. Choose the Message board code or the Linked Message Board code and paste that into your post.
Those codes, similarly look like
and end up looking like