images can be send but are not drawn correctly

server.ino

@@ -7,9 +7,36 @@ void handleRoot() {
   server.send(200, "text/html", index_html);
 }
 
-void handleShow() {
+void handleUpload() {
+  if (server.hasArg("plain") == false) {
+    server.send(400, "text/plain", "body not received");
+    return;
+  }
+  String body = server.arg("plain");
+  DynamicJsonDocument doc(8192);
+  deserializeJson(doc, body);
+  JsonArray arr = doc.as<JsonArray>();
+  int row = 0;
+  for (JsonVariant val : arr) {
+    int col = 0;
+    for (JsonVariant val2 : val.as<JsonArray>()) {
+      long color = strtol(val2.as<const char*>(), NULL, 16);
+      new_image[row][col] = { (unsigned short)col, (unsigned short)row, (uint32_t)color };
+      col++;
+    }
+    row++;
+  }
+  
+  pixels.clear();
+  drawImageFromArr(0, 0);
+  pixels.show();
+  server.send(200, "text/plain", "OK");
+}
+
+void handleShowSaved() {
+  pixels.clear();
+  drawImageFromSaved(0, 0, 0);
   pixels.show();
-  drawImageFromArr(0, 0, 0);
   server.send(200, "text/plain", "OK");
 }
 
@@ -23,7 +50,8 @@ void start_server() {
   Serial.println(WiFi.localIP());
 
   server.on("/", handleRoot);
-  server.on("/show", handleShow);
+  server.on("/show-saved", handleShowSaved);
+  server.on("/upload", HTTP_POST, handleUpload);
   server.begin();
 }