No, you can't do what you want. That requires a script to run to pop out the image. And you cannot embed scripts in you posts.

You can create a link to the larger picture. So, if someone clicks on it, they will go to a page, that is the larger picture.


< A href="www.mypicture.com/picture.jpg">
< img src="www.mypicture.com/picture.jpg" />
< /A>


In steemit com the picture gets sized to 672 px wide.
If they click on the picture, they will go to mypicture com and view the full picture size.