Different Desktop and Mobile Images without extra padding

Site URL: https://www.gruntstylefoundation.org

Hello - I need two different images on desktop and mobile and have achieved this with the code below but now there is extra space where the other image should go but is hidden.  Is there any way to eliminate that?

@media screen and (max-width: 640px) {
  #block-yui_3_17_2_1_1660069934451_52093 {
  display: none;
  }
}

@media screen and (min-width: 641px) {
#block-yui_3_17_2_1_1661390148186_107977 {
display: none;
  }
}
 

Which page are you referring to? I don't see it on homepage