HOW TO INSERT AUTHOR PICTURE IN POSTED BY LINE

1.Log in to your dashboard--> layout- -> Edit HTML
2.Click on "Expand Widget Templates"
3.Scroll down to where you see this:

<p class='post-footer-line post-footer-line-1'>
<span class='post-author'>
<b:if cond='data:top.showAuthor'>
<data:top.authorLabel/> <data:post.author/>
</b:if>
</span>

4.Replace <data:post.author/> with below code.

<a href="URL OF YOUR BLOG"><img src="URL OF YOUR PICTURE" /></a>

5.Click on "Save Templates" and refresh your site.
Note : Remember to give your real information to URL OF YOUR BLOG and URL OF YOUR PICTURE.