How do I remove the white/blank margins on my images in mobile view?

[naydeity]

When viewing images on my site on mobile, not only are they slightly blurry because they've been compressed but there is a white margin around the photos which makes them even smaller and more difficult to view (which is important since they are comic strips with small details). Is there a way to remove the white border around the images so that the edges of the images touch the edges of the mobile screen? I also don't have a premium account so I might have limited access to CSS options. Thanks in advance!

This is an example of the white border/blurriness I'm referring to:

[Adam7]

Image quality aside, I'm seeing the same amount of padding between the two images on both the mobile site and desktop site. You could reduce that on both by clicking on each element in the editor, selecting the spacing option, then setting the top and bottom margins to 0px (they are both 10px right now). 

[naydeity]

Hi Adam,

Sorry for not specifying, I meant the margins on the left and right of the images (which are already reduced to 0px). This is because I am mostly worried about increasing visibility and not so much about how close the images are to each other on the top and bottom. Is there any way to minimize these margins (especially on mobile) through CSS or otherwise?