h3 tag text/image replacement, does this hurt seo?

Question

I'm trying to "replace" text with an image in all of my h3 tags. I want the image to be in the html to avoid multiple h3 classes as this is being done for a portfolio and there will be about 10 h3 tags on the page. My image is 156x44. My question is, will this be viewed as an attempt to hide, stuff keywords by google for seo purposes? If it will then does anyone know a better way to accomplish this?

CSS:

h3 {
    display: block;
    width: 156px;
    height: 44px;
    overflow: hidden;
}

Html:

<h3><img src="images/project001.png" alt="Project 001" />Project 001</h3>

Answer 1

Matt Cutts addresses this question himself over at threadwatch. Pretty much he says to freely do text replacement, just don't try anything spamy like keyword stuffing. Later he clarifies that they:

...flag text that appears to be hidden using CSS at Google. To date we have not algorithmically removed sites for doing that. We try hard to avoid throwing babies out with bathwater.

So they might not be penalizing sites at all at this time for using CSS to hide text.