Make images same size

Hi

Is it possible to make all images in the preview gallery be the same size? But when they are shown in the Light Box they will be their original size?

See my attached image for further clarification:

https://drive.google.com/file/d/1m084CrkEbpVcrVm63rzvM_9u0-NZGkWu/view?usp=sharing

Regards Peter

The page I need help with: [log in to see the link]