Is there a way to make this image smaller by using LaTeX code?
Use the following syntax (where the height is in pixels, you can of course customize it):
<img src="http://i.stack.imgur.com/HfpSm.png" height="123">
You can also change the width, or both the height and the width (if you don't mind changing the aspect ratio):
<img src="http://i.stack.imgur.com/HfpSm.png" width="100" height="200">
Imgur automatically creates several different sized for images, you can get them by appending
l to the filename (before the extension).
See the following examples: