Easy Media Gallery – Thumbnails stretched on iphone

Hi, working on an art gallery website.

https://www.emmaknowles.co.uk running on twentyfourteen theme using Easy Media Gallery

two galleries up and running which are shown on the Gallery Menu Page
https://www.emmaknowles.co.uk/?page_id=18

Missing
https://www.emmaknowles.co.uk/?page_id=423

and Mugshot
https://www.emmaknowles.co.uk/?page_id=535

both look fine on ipad pc etc when you click on each gallery’s page
but iphone 4S stretches the thumbnails on the gallery page, but not when you click to see full size..
I have tried with Chrome and Safari

Is this a problem with twentyfourteen or Easy Media Gallery?
I am fairly certain that these thumbs did resolve properly originally.