Nextgen Thumbnail Picture uploading showing half picture

Hello everyone,

i am using Nextgen Gallery Plugin in website, when i upload pictures, Thumbnail inside picture unable to see in full outlook just can see half of the picture or some part of the picture but when click on the picture its display in full resolution with full contents , for example check my page

https://nayab.com.hk/dinosaurs-3.

is there anyway to fit any size, image inside Thumbnail without resizing the image size as i need High resolution pictures for my site and i want the image to be display in full outlook, i mean the small thumbnail should be look exactly the same as its display in large image. and all thumbnail size should be same. for example like this page, i need,

https://nayab.comli.com/?page_id=29

looking forward to your early response

https://www.ads-software.com/extend/plugins/nextgen-gallery/