@kullschmittgall , are you using a custom module or hubspot image module? If hubspot image module, and admittedly it’s not ideal you could add both images and use the mobile toggle functionality now available in themes (see here for how to set it up if it’s not already on your theme: Accounts Dashboard | HubSpot
For this requirement, you can create a custom module. First, you have to add two images add two different divs’s and add your images separately in that div. Now one div is for the desktop view and the second one is for the mobile. Now add display none class in mobile div. so that only desktop images displays.
Now you have to add the media query on 481px. where you have to display block the mobile div and display none the desktop. So that mobile image is display and desktop image not.