diff --git a/index.html b/index.html
index 6eed2ee..ad57ff3 100644
--- a/index.html
+++ b/index.html
@@ -122,6 +122,10 @@
       width: 100%;
     }
 
+    .upload-note {
+      max-width: 400px;
+    }
+
     .byte-input {
       min-height: 160px;
       min-width: 360px;
@@ -252,6 +256,7 @@
       <section class="sub-section">
         <div class="column" id="file-input-column">
           <h2 class="sub-section-title">1. Select image</h2>
+          <div class="note upload-note">All processing is done locally in your browser; your images are not uploaded or stored anywhere online.</div>
           <input type="file" id="file-input" name="file-input" multiple/><br />
         </div>
         <div class="column column-center">