i would worry less about titles, and get rid of that giant watermark that totally kills the sell value of the image. it will print like that, and i can't imagine anyone who would want something with that huge word on it. not to mention it's cropped off in places. you also have very few keywords and descriptions. for the that old church - you only have old church as a keyword. no one will find you that way.
so the titles aren't that important, it won't attract sales. the watermark will discourage sales, and they won't find you because you only have 2-3 words. the lack of descriptions means your invisible to google also.
Mike is right. Your keywords should describe everything in your photo. For Lavirinthos (why that name? Is it from the place in Crete?) someone looking for a snail on a rock would never find your picture. At least that one should have Snail and Rock in the description, and I would add Gastropod, Mollusc, Mollusk, together with the country/place it was photographed in - Greece, Greek, Crete, Cretan, Lavirinthos if that is where it was.