Resize photos for mobile

Site URL: https://gabriel-vargas.com/work/metricbeat

Hi, 

I don't know how to resize for mobile the photos that are at the top of every page of my four projects. Can anyone please help me? I attached the screenshot of desktop and mobile.

Thanks! 

Edit 4 projects >> Add a Code Block (any where in page) >> paste this code

<style>
  @media screen and (max-width:767px) {
  article section:first-child {
    min-height: unset !important;
    height: 35vh;
}
  }
</style>

Then save & reload the site

Thanks! It worked!