Hi @jeanelleats,

I hope you are well today and thank you for your questions.

My featured images show up huge in my post. How can I change the picture size to a smaller size, say 400 pixels height and retain the proportions of the original picture?

You can achieve it on single post pages by adding the following CSS code in the Custom CSS code option of your theme on the below path.

Admin Area -> Appearance -> Theme Settings -> Custom Code -> CSS Code

.single-post #content .post-thumbnail {
    max-width: 400px;
    display: table;
    margin: 0 auto;
}

Also, my blog posts will not create a break, even if I put in <br>. What has worked is <br class=””>, but the breaks are WAY too thick. I want to be able to have normal breaks appear when I edit in visual mode!

You can create line break on your site as described in the following pages.

https://premium.wpmudev.org/blog/daily-tip-manually-insert-a-line-break-in-wordpress/

https://clickwp.com/kb/understanding-paragraphs-and-line-breaks-in-wordpress/

http://www.wpexplorer.com/wordpress-line-break/

If it still doesn’t work for you then could you please share me the page URL from your site where it is not displaying and also tell me where you want to add line break on that page so that i can troubleshoot it?

Best regards,
Shufflehound team