don't set background image in .board-canvas too

client/lib/utils.js

@@ -4,7 +4,7 @@ Utils = {
   setBackgroundImage(url) {
     const currentBoard = Utils.getCurrentBoard();
     if (currentBoard.backgroundImageURL !== undefined) {
-      $(".board-wrapper,.board-wrapper .board-canvas").css({"background":"url(" + currentBoard.backgroundImageURL + ")","background-size":"cover"});
+      $(".board-wrapper").css({"background":"url(" + currentBoard.backgroundImageURL + ")","background-size":"cover"});
       $(".swimlane,.swimlane .list,.swimlane .list .list-body,.swimlane .list:first-child .list-body").css({"background-color":"transparent"});
     } else if (currentBoard.color !== undefined) {
       currentBoard.setColor(currentBoard.color);