Finally! Found a nice solution to this problem. So simple and working 🙂 Hope it helps you!
<a href="https://plus.google.com/share?url=ADD_YOUR_URL" >
<img src="path_to_your_image" alt="Google+" title="Google+"/>
</a>
Source: http://notesofgenius.com/how-develop-custom-google-plus-button/