You have a couple of options for attaching images in these forums:
You can insert a link to an image hosted on this site or another website using the little chain icon on the toolbar in the forum post "Body" section.
Example link to photo on this site: 2018 D.I.C. Ride start
Example link to photo on another site: 1960 Manx
You can also use the same link tool to insert a clickable email link.
Example clickable e-mail link: Help Desk Email Address
NOTE: You can test these links while editing your post by holding down the Control key (or Command key on Macs) and clicking your link.
You can also attach images or other files to your posts using the "Choose files" button in the "Attachments" section below the body section on the post editing page. (See attached example file.)
NOTE: Unfortunately, for some, only Administrators are able to insert and embed images within the body text of forum posts.