Yes, you can attach and/or insert up to four images.
– from the Forum’s help page accessible from the drop down menu above:
Users may attach up to four files to each of their posts. The maximum size per file is 3MB. During the attachment process, there are options to ‘Set file Caption’, ‘Insert into content’ and to remove the file. Unless you select ‘Insert into Content’, the file will simply show as a thumbnail within the footer of your post and will open as an overlay when clicked on.
Chris (Calohan): There are two ways to add images to a post. One is as Chris (Sanderson) suggested. The other is to link to an image that is already online somewhere using the picture icon in the compose window toolbar.* Kevin keeps asking people to upload images to the Community section of this site; you can post an image there then use that URL to post the image in the forums as well.
*NB: the forum software will only accept https links; http links will be blocked.
Mike Nelson Pedde