Issue with Thumbnail preview in Admin Grid

[kanchevout612a]

Hi all,

I hope this is the correct section to ask my question.

So i am just learning how to create custom modules in Magento 2. I just created my first one via one tutorial which shows how to display thumbnails in the Admin Grid. 

In the tutorial when you click the thumbnail it pops new window with the image in it. Same as for the product listing thumbnail.

The issue i have is that the pop-up shows empty for some reason:

I know this has to do with the Ui/Component/Listing/Column/Thumbnail.php which i am also modifying. I will appreciate some pointers what might be causing the issue and not displaying the picture in the pop-up.

[kanchevout612a · Accepted solution]

Solved.. I was missing $item[$fieldName . '_orig_src']  in my prepareDataSource method in the Thumbnail.php

after adding this now it is showing ok.