[Opserty]

I don't know what the variable is for number of blogs but you can use an if condition in the postbit(_legacy) template. It would go something like:

<if condition="$post[blogs]">
    <img src="path/to/blue/img.gif" alt="$post[username] has $post[blogs] blogs" />
<else />
    <img src="path/to/grey/img.gif" alt="$post[username] has no blogs" />
</if>

I'm not sure if $post[blogs] is the correct variable but you can try looking for yourself or wait till someone comes along who knows.