diff --git a/matemat/__main__.py b/matemat/__main__.py
index bcfd877..d3dd5e8 100644
--- a/matemat/__main__.py
+++ b/matemat/__main__.py
@@ -67,8 +67,9 @@ def get_thumbnail(resource: str, filename: str):
     static: str = os.path.abspath(config['staticroot'])
     rpath: str = os.path.join(static, 'upload/thumbnails', resource)
     resp = bottle.static_file(filename, root=rpath)
-    if resp.status_code != 200:
+    if resp.status_code >= 400:
         resp = bottle.static_file('default.png', root=rpath)
+    resp.headers['Cache-Control'] = 'public, max-age=0;'
     return resp
 
 
diff --git a/templates/admin.html b/templates/admin.html
index 2472676..6f53815 100644
--- a/templates/admin.html
+++ b/templates/admin.html
@@ -112,7 +112,7 @@
 	      <td>{{ product.price_non_member | chf }}</td>
 	      <td>{{ '✓' if product.custom_price else '✗' }}</td>
 	      <td>{{ '✓' if product.stockable else '✗' }}</td>
-	      <td><img style="height: 2em;" src="/static/upload/thumbnails/products/{{ product.id }}.png?cacheBuster={{ now }}" alt="Picture of {{ product.name }}" draggable="false"></td>
+	      <td><img style="height: 2em;" src="/static/upload/thumbnails/products/{{ product.id }}.png" alt="Picture of {{ product.name }}" draggable="false"></td>
 	      <td>
 		<div class="btn-group" role="group">
                   <a class="btn btn-primary" href="/modproduct?productid={{ product.id }}">Edit</a>
@@ -134,7 +134,7 @@
 
 	  <div class="col-sm-2 g-4">
 	    <div class="card h-100">
-	      <img class="card-img-top" src="/static/upload/thumbnails/users/default.png?cacheBuster={{ now }}" alt="Default user avatar" />
+	      <img class="card-img-top" src="/static/upload/thumbnails/users/default.png" alt="Default user avatar" />
 	      <div class="card-body">
 		<label class="card-title" for="admin-default-images-user">Default user avatar</label>
 		<div class="card-text">
@@ -146,7 +146,7 @@
 
 	  <div class="col-sm-2 g-4">
 	    <div class="card h-100">
-	      <img class="card-img-top" src="/static/upload/thumbnails/products/default.png?cacheBuster={{ now }}" alt="Default product image" />
+	      <img class="card-img-top" src="/static/upload/thumbnails/products/default.png" alt="Default product image" />
 	      <div class="card-body">
 		<label class="card-title" for="admin-default-images-product">Default product image</label>
 		<div class="card-text">
diff --git a/templates/modproduct.html b/templates/modproduct.html
index 77c34a6..0fe4867 100644
--- a/templates/modproduct.html
+++ b/templates/modproduct.html
@@ -36,7 +36,7 @@
       <input class="form-control" id="modproduct-balance" name="stock" type="text" value="{{ product.stock }}" /><br/>
 
       <label class="form-label" for="modproduct-image">
-        <img height="150" src="/static/upload/thumbnails/products/{{ product.id }}.png?cacheBuster={{ now }}" alt="Image of {{ product.name }}" />
+        <img height="150" src="/static/upload/thumbnails/products/{{ product.id }}.png" alt="Image of {{ product.name }}" />
       </label><br/>
       <input class="form-control" id="modproduct-image" type="file" name="image" accept="image/*" /><br/>
 
diff --git a/templates/moduser.html b/templates/moduser.html
index 38b12c3..29d292b 100644
--- a/templates/moduser.html
+++ b/templates/moduser.html
@@ -49,7 +49,7 @@
         <input class="form-control" id="moduser-account-balance-reason" type="text" name="reason" placeholder="Shows up on receipt" /><br/>
 
         <label class="form-label" for="moduser-account-avatar">
-            <img height="150" src="/static/upload/thumbnails/users/{{ user.id }}.png?cacheBuster={{ now }}" alt="Avatar of {{ user.name }}" />
+            <img height="150" src="/static/upload/thumbnails/users/{{ user.id }}.png" alt="Avatar of {{ user.name }}" />
         </label><br/>
         <input class="form-control" id="moduser-account-avatar" type="file" name="avatar" accept="image/*" /><br/>
 
diff --git a/templates/productlist.html b/templates/productlist.html
index a0f8c47..a335bd3 100644
--- a/templates/productlist.html
+++ b/templates/productlist.html
@@ -66,7 +66,7 @@
           </span>
 	{% endif %}
       </div>
-      <img class="card-img-bottom" src="/static/upload/thumbnails/products/{{ product.id }}.png?cacheBuster={{ now }}" alt="Picture of {{ product.name }}" draggable="false"/>
+      <img class="card-img-bottom" src="/static/upload/thumbnails/products/{{ product.id }}.png" alt="Picture of {{ product.name }}" draggable="false"/>
       {% set pstock = stock.get_stock(product) %}
       {% if pstock is not none %}
 	<div class="card-img-overlay d-flex flex-column justify-content-end">
diff --git a/templates/settings.html b/templates/settings.html
index 5d3e595..d9578ae 100644
--- a/templates/settings.html
+++ b/templates/settings.html
@@ -28,7 +28,7 @@
       <div class="col-xl-1 col-md-2 col-sm-3 col-4 mb-3">
 	      <div class="card text-bg-light">
 	        <div class="card-header">{{ authuser.name }}</div>
-	        <img class="card-img-bottom" draggable="false" src="/static/upload/thumbnails/users/{{ authuser.id }}.png?cacheBuster={{ now }}" alt="Avatar of {{ authuser.name }}">
+	        <img class="card-img-bottom" draggable="false" src="/static/upload/thumbnails/users/{{ authuser.id }}.png" alt="Avatar of {{ authuser.name }}">
 	      </div>
       </div>
     </div>
diff --git a/templates/userlist.html b/templates/userlist.html
index 8086421..9a32a26 100644
--- a/templates/userlist.html
+++ b/templates/userlist.html
@@ -10,7 +10,7 @@
 	  <div class="card-header">
 	      {{ user.name }}
 	  </div>
-	  <img class="card-img-bottom" src="/static/upload/thumbnails/users/{{ user.id }}.png?cacheBuster={{ now }}" alt="Avatar of {{ user.name }}" draggable="false"/>
+	  <img class="card-img-bottom" src="/static/upload/thumbnails/users/{{ user.id }}.png" alt="Avatar of {{ user.name }}" draggable="false"/>
 	</a>
       </div>
     {% endfor %}