<img src=" Your Image Url " />
Follow The Steps.
1.Log in to your blogger account.
2.Next go to edit html then check expand widget templates.
3.Look for the following codes.
4.Paste the main code under it.
If you want the icon to appear before post title then you need to paste the main code under the first code in step 3.
But if you want the icon to appear after the post title then all you need is the 2nd code and paste the main code under it.Good Luck.