How to maintain picture/gif size between mobile and desktop

Hey,

I'm working on a site where on the mainpage I have gifs inserted into the 'page setting -> media' so that when people click the gif it takes them to the corresponding page 

The gifs look good when viewing on mobile, but when I open on desktop they stretch (I have text on them that gets cut off)

Is there a way to maintain image size between the 2 modes?

Can you share link to your site?

Is there a way for me to link the site when its not live?