Unable to change size of image/logo in footer on mobile

Hi Sue, this is a limitation in the classic editor as on mobile it doesn't render the spacer blocks basically.

You can manage this sizing separately if you upgrade the section to Fluid Engine, but if you'd like to keep it as is, paste this code into the Custom CSS panel in the Design menu:

@media only screen and (max-width: 768px) {
  #block-yui_3_17_2_1_1690487871110_7358 {
    width: 40%;
    margin: 0 auto;
  }
}

You can adjust the percentage to whatever you'd like it to be 😊