Does Google consider the alt text in a linked graphic?

[annej]

I am thinking about switching to a graphic logo that will link to my homepage from all pages on one of my sites.

Do I lose any impact that text links would have?

[tedster]

Yes, Google considers the alt attribute's content in a linked graphic - but because that text is essentially not visible on the page, it isn't trusted as highly as visible anchor text. It's just not as dependable as a relevance signal.

In this case, you are asking specifically about links to your home page. Google has taken a number of steps to minimize the games people were playing with alt attributes in their Home links. I think you can change to a graphic without much negative effect. Keep your alt text very direct - "example.com home page" or something like that. Your backlinks from other sites should have anchor text that can carry your rankings for you.