diff --git a/index.php b/index.php
index a3354ea..bf73fbe 100644
--- a/index.php
+++ b/index.php
@@ -119,6 +119,7 @@
 
                 <script>
                     const canvas = document.getElementById("canvas-input");
+                    const bits = document.getElementById("image-bits");
                     const ctx = canvas.getContext("2d");
 
                     const pen = ctx.createImageData(2, 2);
@@ -131,7 +132,11 @@
 
                     var drawing = false;
                     canvas.onmousedown = function() { drawing = true; }
-                    document.onmouseup = function() { drawing = false; }
+                    document.onmouseup = function() {
+                        drawing = false;
+                        // write image-bits for posting
+                        bits.value = "101";
+                    }
 
                     canvas.onmousemove = function() {
                         if (drawing) {