Maybe the ability to wrap the block or something?
Not sure if this makes sense, but hope someone van help...
Do you have a web page address where you are trying to align images?
To better describe your issue, can you provide a screenshot/mockup of what you are trying to do?
Of course you can always override any CSS by adding new CSS rules to your main CSS file (which often is a LESS file, but that also takes CSS code).
A simple way to override styles is to go into the dashboard -> go to a page -> click the cogwheel -> click 'design' -> pick the theme 'customise' link -> scroll down and there you will often find 'Advanced - custom CSS' where you can just add styles.
Code correct solution: If you have a theme in your Packages, you can override it by copying it's CSS to its **respective** >>/>>Application/>>Themes>>Nameoftheme>>cssfolder>>main.css
Which sometimes means you might have to copy its 'LESS includes' as well. All depending on your theme.