For years I've been writing my HTML for images like this:

<img src="/picture.jpg" alt="my picture" >

But I recently ran a audit of my site using Raven SEO tools and it reported loads of errors which I was really surprised with.

When I went through the report 99 % of these errors were because of missing image title text.

I know that the title text for an image can display a little pop over when you hover over an image, but apart from that what's the purpose and does it have an effect on SEO?

Also if you were to implement it, what would you put in there? Would you just put the same info that's in the alt attribute? i.e. alt="my picture" title="my picture"