How to make map image in 2 different sizes?

As you can see on
https://anshell.com/florida-has-67-counties-and-at-least-953-cities
I added to try & see how it look 2 50x50px small maps from
https://en.wikipedia.org/wiki/List_of_counties_in_Florida
I need your help in explaining to me how to upload in 2 different sizes.
We can keep small (50x50) on a page, but if a visitor hovers over it (or click), it will be in a bigger size to view it. Maybe: 241×240 pixels or 481×480 pixels or 770×768 pixels. I don’t know which one is better & not so heavy for a site to have. Need your advice.
BTW remember I asked you about tax info links from each county to listings? Now I need only from my 3 neighboring counties, but in the future, we will need links from all 67 counties! That’s why I decided to make this post, so you’ll see an idea 😃

The workaround here is to put link inside the image and put the uploaded link as url. example

[![Image Alt Text]
(URL of the image)]
(URL of the image as link)

live example

This will output

-Randy