displayign images works with some dim

server.ino

@@ -13,6 +13,7 @@ WebServer server(80);
 Pixel new_image[16][16];
 char* fileContent = nullptr;
 size_t fileContent_len = 0;
+String upload_error_message = "";
 
 
 void handleRoot()
@@ -29,6 +30,7 @@ void handleUploadPage()
 void handleBmpUpload() {
   HTTPUpload& upload = server.upload();
   if (upload.status == UPLOAD_FILE_START) {
+    upload_error_message = "";
     if (fileContent) {
       free(fileContent);
       fileContent = nullptr;
@@ -46,11 +48,18 @@ void handleBmpUpload() {
       char header[54];
       memcpy(header, fileContent, 54);
 
+      int dataOffset = *(int*)&header[10];
       int width = *(int*)&header[18];
       int height = *(int*)&header[22];
+      short bitsPerPixel = *(short*)&header[28];
+
+      if (bitsPerPixel != 24) {
+        upload_error_message = "Unsupported BMP format: Only 24-bit BMPs are supported";
+        return;
+      }
 
       if (width < 1 || width > 48 || height < 1 || height > 16) {
-        server.send(400, "text/plain", "Invalid image dimensions");
+        upload_error_message = "Invalid image dimensions";
         return;
       }
       
@@ -59,20 +68,16 @@ void handleBmpUpload() {
 
       // Read pixel data
       int row_padded = (width*3 + 3) & (~3);
-      char* pixel_data = fileContent + 54;
+      char* pixel_data = fileContent + dataOffset;
 
-      for (int y = height - 1; y >= 0; y--) {
+      for (int y = 0; y < height; y++) {
         for (int x = 0; x < width; x++) {
-          saved_images[0].pixels[y][x].b = pixel_data[y*row_padded + x*3 + 0];
-          saved_images[0].pixels[y][x].g = pixel_data[y*row_padded + x*3 + 1];
-          saved_images[0].pixels[y][x].r = pixel_data[y*row_padded + x*3 + 2];
+          int bmp_row = height - 1 - y;
+          saved_images[0].pixels[y][x].b = pixel_data[bmp_row*row_padded + x*3 + 0];
+          saved_images[0].pixels[y][x].g = pixel_data[bmp_row*row_padded + x*3 + 1];
+          saved_images[0].pixels[y][x].r = pixel_data[bmp_row*row_padded + x*3 + 2];
         }
       }
-      
-      pixels.clear();
-      drawImageFromMemoryByIndex(0, 0, 0);
-      pixels.show();
-      server.send(200, "text/plain", "OK");
 
       free(fileContent);
       fileContent = nullptr;
@@ -86,7 +91,7 @@ void handleBmpUpload() {
 void handleShowSaved()
 {
   pixels.clear();
-  drawImageFromMemoryByIndex(0, 0, 0);
+  drawImageFromMemoryByIndex(0, 0, 0, 100);
   pixels.show();
   server.send(200, "text/plain", "OK");
 }
@@ -106,7 +111,11 @@ void start_server()
   server.on("/show-saved", handleShowSaved);
   server.on("/upload-page", HTTP_GET, handleUploadPage);
   server.on("/upload-bmp", HTTP_POST, []() {
-    server.send(200, "text/plain", ""); 
+    if (upload_error_message.length() > 0) {
+      server.send(400, "text/plain", upload_error_message);
+    } else {
+      server.send(200, "text/plain", "Upload OK");
+    }
   }, handleBmpUpload);
   server.begin();
 }