Q:

fix one column containing a responsive image, alongside another column inside modal in bootstrap 4

I have a row containing two columns, one containing an image and the other one containing a list of users in a modal window. 
When the user scrolls down the modal more users are loaded.  I want the image to be fixed when the modal is scrolled down. 
html:
<div class="modal fade" id="recognitionModal" tabindex="-1" role="dialog" aria-labelledby="recognitionModalLabel" aria-hidden="true">
<div class="modal-dialog modal-xl modal-dialog-centered" role="document">
    <div class="modal-content">
        <div class="modal-header">
             <h5 class="modal-title" id="recognitionModalLabel">{% trans 'Lets admire someone today:)' %}</h5>
        </div>
        <div class="modal-body">
            <div class="row">
                <div class="col-12 recognition-container" id="recognizeWho">
                    <div class="row justify-content-center">
                        <!--  I want this column to be fixed -->
                        <div class="col-12 col-lg col-xl-6">
                            <img class="img-fluid" src="{% static 'image/heart.svg' %}" />
                        </div>
                        <div class="col-12 col-lg col-xl-4">
                            <!--  this section also be fixed -->
                            <div class="form-group">
                                <div class="input-group input-group-alternative mb-4">
                                    <input class="form-control form-control-alternative" id="chooseColleague" placeholder="Choose your colleague.." type="text">
                                </div>
                            </div>
                            <!--  while this section is scrolling -->
                            <div>
                                <div class="who-to-recognize-container mb-2">
                                      <div class="who-to-recognize-row d-flex my-2" user_id="2"><div class="px-3 align-self-center"><div class="media"><span class="avatar avatar-sm rounded-circle bg-white shadow-sm border"><span class="text-dark">a</span> </span> <div class="media-body ml-2"><span class="username mb-0 text-sm font-weight-bold">admin </span> <small class="occupation text-muted d-block">Developer</small></div></div></div><div class="flex-grow-1 align-self-center mt-2"><div class="text-right"><span class="select-row-radio"></span> </div></div></div>
                                      <div class="who-to-recognize-row d-flex my-2" user_id="2"><div class="px-3 align-self-center"><div class="media"><span class="avatar avatar-sm rounded-circle bg-white shadow-sm border"><span class="text-dark">a</span> </span> <div class="media-body ml-2"><span class="username mb-0 text-sm font-weight-bold">admin </span> <small class="occupation text-muted d-block">Developer</small></div></div></div><div class="flex-grow-1 align-self-center mt-2"><div class="text-right"><span class="select-row-radio"></span> </div></div></div>
                                      <div class="who-to-recognize-row d-flex my-2" user_id="2"><div class="px-3 align-self-center"><div class="media"><span class="avatar avatar-sm rounded-circle bg-white shadow-sm border"><span class="text-dark">a</span> </span> <div class="media-body ml-2"><span class="username mb-0 text-sm font-weight-bold">admin </span> <small class="occupation text-muted d-block">Developer</small></div></div></div><div class="flex-grow-1 align-self-center mt-2"><div class="text-right"><span class="select-row-radio"></span> </div></div></div>
                                      <div class="who-to-recognize-row d-flex my-2" user_id="2"><div class="px-3 align-self-center"><div class="media"><span class="avatar avatar-sm rounded-circle bg-white shadow-sm border"><span class="text-dark">a</span> </span> <div class="media-body ml-2"><span class="username mb-0 text-sm font-weight-bold">admin </span> <small class="occupation text-muted d-block">Developer</small></div></div></div><div class="flex-grow-1 align-self-center mt-2"><div class="text-right"><span class="select-row-radio"></span> </div></div></div>
                                      <div class="who-to-recognize-row d-flex my-2" user_id="2"><div class="px-3 align-self-center"><div class="media"><span class="avatar avatar-sm rounded-circle bg-white shadow-sm border"><span class="text-dark">a</span> </span> <div class="media-body ml-2"><span class="username mb-0 text-sm font-weight-bold">admin </span> <small class="occupation text-muted d-block">Developer</small></div></div></div><div class="flex-grow-1 align-self-center mt-2"><div class="text-right"><span class="select-row-radio"></span> </div></div></div>
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>
</div>

this is the jsfiddle link modal

A:

Add this class to your img element:
.sticky {
  position: -webkit-sticky;
  position: sticky;
  top: 0;
}

