seo - images and h1

Question

I like to have logos instead of text on my h1 tags, is it better to have both & will it effect my SEO 

<div id="hdr-top-logo">
 <h1>                   
  <a href="/">
   <img src="logo.jpg" alt="keywords and title" />
  </a>
 </h1>
</div>

 Will I suffer in SEO if I input only keywords in the alt tags ?

Answer 1

SEO is speculative at best.

Generally, the accepted convention is to use where appropriate and you won't suffer. For example, in your code I would write something like this:

<div id="hdr-top-logo">

 <h1>                   

  <a href="/" title="Blahblah.com logo">

   <img src="logo.jpg" alt="Blahblah logo" />

  </a>

 </h1>

</div>

The advantage of having text instead of a logo is not much and alt + title should be descriptive, don't just put in a bunch of keywords otherwise, you will suffer SEO.