fix: save slide feature works

Author: HarshKhandeparkar

src/components/Page/save-slide.js

@@ -2,8 +2,8 @@ import { PNG } from 'pngjs/browser';
 
 export function saveSlide(pixels) {
   const png = new PNG({
-    width: pixels.length,
-    height: pixels[0].length
+    width: pixels[0].length,
+    height: pixels.length
   })
 
   for (let y = 0; y < pixels.length; y++) {