diff --git a/app/models/concerns/alchemy/picture_thumbnails.rb b/app/models/concerns/alchemy/picture_thumbnails.rb
index ef3a234e81..cffc857407 100644
--- a/app/models/concerns/alchemy/picture_thumbnails.rb
+++ b/app/models/concerns/alchemy/picture_thumbnails.rb
@@ -84,7 +84,7 @@ def thumbnail_url_options
         crop_from: crop && crop_from.presence || default_crop_from&.join("x"),
         crop_size: crop && crop_size.presence || default_crop_size&.join("x"),
         flatten: true,
-        format: picture&.image_file_format || "jpg"
+        format: "webp"
       }
     end
 
diff --git a/app/views/alchemy/admin/pictures/_picture.html.erb b/app/views/alchemy/admin/pictures/_picture.html.erb
index 474f302453..7a1abac4c1 100644
--- a/app/views/alchemy/admin/pictures/_picture.html.erb
+++ b/app/views/alchemy/admin/pictures/_picture.html.erb
@@ -20,7 +20,7 @@
     </sl-tooltip>
   </span>
   <% end %>
-  <% picture_url = picture.url(size: preview_size(@size), flatten: true) %>
+  <% picture_url = picture.url(size: preview_size(@size), flatten: true, format: "webp") %>
   <% image = image_tag(picture_url || "alchemy/missing-image.svg", alt: picture.name) %>
   <% if can?(:edit, picture) && picture_url %>
     <%= link_to(
diff --git a/app/views/alchemy/admin/pictures/_picture_to_assign.html.erb b/app/views/alchemy/admin/pictures/_picture_to_assign.html.erb
index 2ccdaaf993..0443754ec8 100644
--- a/app/views/alchemy/admin/pictures/_picture_to_assign.html.erb
+++ b/app/views/alchemy/admin/pictures/_picture_to_assign.html.erb
@@ -2,7 +2,7 @@
   <sl-tooltip content="<%= Alchemy.t(:assign_image) %>">
     <%= link_to(
       image_tag(
-        picture_to_assign.url(size: preview_size(size), flatten: true) || "alchemy/missing-image.svg",
+        picture_to_assign.url(size: preview_size(size), flatten: true, format: "webp") || "alchemy/missing-image.svg",
         alt: picture_to_assign.name
       ),
       alchemy.assign_admin_picture_path(