hover Image hover change very slow and glitchy - code block not working well

Site URL: https://www.workshopandmachine.com/homepageprojects

Hi, On a homescreen I've created images that change when the mouse hovers over them. I created them with custom code blocks. This client does not have the premium features so I am not able to Inject custom code or scripts to the page. The code blocks load, but very slowly and glitchy initially when the browser opens it. 

This is the code I used: <a href="https://www.workshopandmachine.com/rising-sealevelscompetition"><div id="img-hover2"></div></a>

After a while of waiting for the images to load and hovering over them they work fine, but every new user cannot have this problem where the hover over is glitchy. Any solutions/ suggestions? 

Please help!

You can consider using Image Block + CSS code to do this (Your plan supports CSS code)

I wrote a guide here

Or you can add an Image Block, then we will give the code