I've always had this problem when embedding flickr photos and the urls, or just whenever I solely wish to post the url address, and then it turns into the video box, regardless.
As you mentioned, in order for it to show properly you need to either post your entry, then re-edit it "go advanced" to uncheck the
embed media automatically button to let it display as you wanted in the first place; or you can hotlink the picture only, and then [code] the link you wanted to embed.
I know the first option is the ideal, but the automatically-embed feature gets to be so quarrelsome at times that it mangles the original coding, and then to have to re-edit it each time you'd like to make a photo-clickable is what has made me avoid this practice.
---------- Post added at 02:45 PM ---------- Previous post was at 02:42 PM ----------
I usually do this instead: picture / title+author underneath
Surf by fiatguy85
{unchecked box "Automatically embed media (requires automatic parsing of links in text to be on)"
unchecked box "Automatically retrieve titles from external links"}