To the OP,
If you want to post a photo in a link here on AN,
one simple way to do that,
is use IMGUR.
imgur: the simple image sharer
^If you click on that, you will see something about "register today" but, you do NOT have to register or any such thing, just look to the upper right hand side of the screen for "UPLOAD PHOTOS"
Under the "upload photos"
are two buttons, one says "COMPUTER" and the other says "web".
click on "computer"
then follow Nurse156 advice above---- select the photo from your own photos saved in your own computer,
(make sure your computer opens to photos, if it opens on documents or someplace, then click on the 'photos' so all your photos open up for you to choose one...)
Pick your photo you want to upload
next, a screen appears on IMGUR, and you again click on the "Upload"
and your photo uploads onto IMGUR.
Then, after photo has uploaded,
you will see your own photo sitting there,
and multiple options to share it will be along the right hand side of the screen.
Easy way, instead, is just RIGHT-CLICK on your photo,
select "copy link location"
then go to comment, and hit "paste". Your post will now have a link embedded into it, like this.
Hope that helps. You can also use IMGUR to post photos onto facebook comments, too.