Oh that's an easy one. Stick this whereever you have the BBCode page.
Code:
$image = getcurrentimage($aid);
article_content = article_content."
<textarea name='textarea' cols='50' rows='4'>[img]".$image."[/img]
</textarea>";
That goes and gets the actual image being used. However the only problem with this version is it will not go and get the new image if the adoptable is leveled up.