Based on the comments, I would guess that you want an input field that has that HTML code as the default text. You must use character reference codes for quotes and less/greater than signs.
<input type="text" value="<a href="http://www.mysite.com/link" target="_blank"><img src="http://www.mysite.com/img.jpg" border="0" alt="mysite.com"></a>" />
(By the way, you mentioned "like in Photobucket" -- you can just look at the site's HTML to see how they do it.)
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…