Sanity-check some graphical LCD-only options

Marlin/src/inc/SanityCheck.h

@@ -376,6 +376,13 @@ static_assert(X_MAX_LENGTH >= X_BED_SIZE && Y_MAX_LENGTH >= Y_BED_SIZE,
 #endif
 
 /**
+ * Custom Boot and Status screens
+ */
+#if DISABLED(DOGLCD) && (ENABLED(SHOW_CUSTOM_BOOTSCREEN) || ENABLED(CUSTOM_STATUS_SCREEN_IMAGE))
+  #error "Graphical LCD is required for SHOW_CUSTOM_BOOTSCREEN and CUSTOM_STATUS_SCREEN_IMAGE."
+#endif
+
+/**
  * SD File Sorting
  */
 #if ENABLED(SDCARD_SORT_ALPHA)