Image Thumbnail in admin order view page

[akhundof]

Dears, i am searching for a module that will show thumbnails in admin order view page. Actually i had tried solutions mentioned in here. But it seems that 2.2.6 version not works with this solution, and actual php class not support this type of get image method.  I looked into marketplace and couldn't find anything useful. Please help me to find this extension, or show me the right way i can get product image in defult.phtml $_item.Thanks in advance.  

PS: This side is broken. 

$image_url = $imageHelper->init($product, 'small_image')->setImageFile($product->getSmallImage())->resize($imagewidth, $imageheight)->getUrl();

[akhundof]

I had crated own module(part of code taken from internet). But unfortunately Admin Order view page gives 500 error when i am enabling this module. 

LINK TO MODULE (ZIP)

Can anyone please review, and say what is wrong with code. Thanks in advance. 

[madhuresan_ramanan]

Hi @akhundof,

I can't able to reach the site. can you check the site?

If my info is useful, give kudos

Best regards
Madhuresan
Bootsgrid

[akhundof]

Link for module