kaled - 10:42 am on Sep 8, 2010 (gmt 0)
the title is not part of the semantic structure of the document.
As John McEnroe would say "You cannot be serious". What definition of semantic are you working with?
Search engines may interpret <img alt> text and weight it according to location, however, I doubt any publish such details of their algos so reliance on guesswork is pretty silly (also reliance on experimental evidence is silly too since such details may be subject to change).