add image next to category under post title (next to author name and date)

Hi,
Need some help! Each category in my navigation menu has an image next to it. A “colour tag” if you will. I’d like the image to show next to the category name that is displayed under the post title.
e.g.

Test Post! (post title)
(date) colour image next to category (edit)

post content

How would I go about doing this? What do I edit in the css and where?
Thanks so much! I’d appreciate any advice!!