If you're sick of that spacing between images in your blog posts then you can follow these steps to manually adjust the CSS settings for your images.
Select the Single Post template in Showit
Go to the Advanced Settings (right sidebar) > Custom CSS section
Copy and Paste the code below into the Custom CSS box:
Things to Know:
This will only apply to images set with Alignment None or Alignment Center
Hard Returns between images will still leave spaces, be sure you're not adding returns between images.
This isn't a perfect science...so give it a try and see how it works.