Use HTML tags. Like this:
Simply replace the url to the AQ logo in the code above (between the quotes but not including the quotation marks) with the url to the pic you want to display.
To get the url of the pic (it has to be online, usually on a website), find the pic you want to post, RIGHT click, then copy the url (web address) of on the popup.
This method is for adding pics to comments. For inserting pics on new posts (articles), it’s easiest to use “add media” button at the top of the WYSIWYG editor above the posting interface.