Adding an image to a Post-Submit message

Site URL: https://raeraeoflight.org/the-beat-goes-on

Hello,

I am a beginner and not very good with HTML.  I'd like to add an image to my post-submit form but have no idea how to construct the HTML.  I have an image ready.  Can anyone walk me through the steps?  Hopefully it's not too complex!  thank you in advance.

Add image to above or under message? Small or big image

small image below the text

6 hours ago, tuanphan said:

Add to Design > Custom CSS

div#page-section-62b1f155094a6840d73319c3 .form-submission-text:after {
    content: "";
    background-image: url(https://cdn.pixabay.com/photo/2022/05/21/09/30/cat-7211080__480.jpg);
    background-size: contain;
    display: block;
    width: 100px;
    height: 50px;
    background-repeat: no-repeat;
    background-position: center center;
}

Thank you so much for the help!  Very much appreciated!