For SmugMug, I can do no better than to point you to AnnieNg's post here:
dprevived.com/t/how-to-embed-photos-into-your-post-from-smugmug-account/1117/
For Flickr, have a look at Naia's post here
dprevived.com/t/how-to-embed-photos-into-your-post-directly-from-flickr/456/
Alan