What is most SEO optimized image HTML code for?

so far i was doing it like this:

&开发者_JAVA百科lt;a href="http://domain.com" title="Keyword"><img src="image.png" alt="Keyword" /></a>

Now, i discovered that images can have title attribute too:

<a href="http://domain.com" title="Keyword"><img src="image.png" alt="Keyword" title="Keyword"/></a>

Is there any other optimization i could pull off to boost image links value?

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I think that's the best you can do really, someone told me to try and make image names as descriptive as possible, for instance:

image_001.jpg --> honda_accord_2009.jpg

Granted image.png is just an example, but it might apply.

That's all I could think of.

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Think of the alt attribute as an alternative text replacement for the image. Imagine for a moment that you had to describe the image to someone who could not see it. That is the sort of information you should be conveying in the alt attribute.

Similar to the alt attribute, title is used for the same purpose. It helps to convey extra information about an element. You can apply the title attribute to most elements but you must give all your images an alt attribute.

In my opinion, having both an alt and a title on an image is redundant, especially if they are conveying the same information.

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I would have to say yes, the title tag would add value to your SEO. Check this link for full details - http://www.seocentral.com/tutorials/alt-title-attributes.html

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Don't over-optimize your links and/or images. As other users pointed out every image should contain an alt-attribute. On decorative images the alt tag should be places but it should be empty since it doesn't convey any information.

The alt tag should describe the meaning of the image within the current context. Imagine trying to explain the image to a blind person. If you can't come up with a good way to explain why the image is relevant there the alt tag should be empty (if the image should be placed there at all)

Check out this article for more information on that: http://www.userfocus.co.uk/articles/alt_text.html

The title tag creates this little popup when you hover over the link or image for about a second. This should be used to give the describe the image and might be a better place to put a keyword.

What you also missed in the question is the filename. If the image is relevant to the topic of the page you could use keyword.jpg or something.

This would also help it in image search engines.