The current theme has css property as width:100% & display:block which prevents positioning of images side-by-side and in their defined size configuration.
Solution:
- Update theme's CSS to suit our use case.
- Use some other theme.
Desired Outcome

Check .nested-img img in inspect/styles tab.
P.S: I tried some of the themes, though they dont impose width:100% but display:block, so anyways theme must be customised.