common/static/common/styles/_extension.sass

@@ -324,9 +324,9 @@
   gap: .8rem
 
 .previews-list-item
-  --preview-thumbnail-max-size: 180px
+  --preview-thumbnail-max-size: calc(12.4rem * 16 / 9)
 
-  align-items: center
+  align-items: start
   background-color:
   border-radius: var(--border-radius-lg)
   border: var(--border-width) solid var(--border-color)
@@ -335,6 +335,7 @@
 
   .previews-list-item-thumbnail
     margin: 0
+    +margin(2, top)
     width: var(--preview-thumbnail-max-size)
 
     .previews-list-item-thumbnail-img
@@ -342,6 +343,7 @@
       background-position: center
       background-size: cover
       border-radius: var(--border-radius)
+      height: 12.4rem
       +make-aspect-ratio('16x9')
 
   .details
@@ -350,6 +352,7 @@
 
     label
       font-size: var(--fs-sm)
+      line-height: var(--lh-sm)
 
     ul
       +list-unstyled

extensions/templates/extensions/manage/components/add_previews.html

@@ -8,7 +8,7 @@
     {% with inlineform=newform|add_form_classes %}
       <div  class="ext-edit-field-row js-ext-edit-field-row">
         <div class="previews-list-item">
-          <div class="align-items-center d-flex previews-list-item-thumbnail ps-3">
+          <div class="d-flex previews-list-item-thumbnail ps-3">
             <div class="js-input-img-thumbnail previews-list-item-thumbnail-img" title="Preview">
               <div class="align-items-center d-flex js-input-img-thumbnail-icon justify-content-center">
                 <i class="i-img"></i>