Default Classic template does not allow to display menu thumbnail image on front-office. To display menu thumbnails in the main menu you need to just follow the below steps.

Go to: Theme root directory > modules > ps_mainmenu > ps_mainmenu.tpl

Now, Copy the below code.

Then place it to just after below line.

Modified file will be look like as below

Now save the changes and clear the cache after uploading menu thumbnails image from the back-office. Your uploaded menu thumbnail image will be visible in main menu on front-side.


Front-office view:

That’s all.