SmugMug is easy. Just navigate to the image you want to share and click on the <Share> icon. It is the middle button on the right side, just above your photo. Select <Get a Link> from the drop down menu.
On the sharing page, scroll down to DIRECT PHOTO LINKS: and select the size image to link to.
This is Medium:
This is Large:
BTW, leave out the asterisks in the HTML tags to post your picture. The asterisk is just a way to have the link show up as text rather than function as an actual link.
Looking forward to seeing your work.
Another of the many Jim's here.