Rollover with jquery

Hi I run a blog: https://bernalheights.org

I want to have a rollover for an image, i found a plug in on
https://frederik.orellana.dk/2008/03/22/image-rollovers-plugin-for-wordpress/
and i followed the instructions to the best of my abilities, but cant seem to get it to work.

i donwloaded the latest version of the jquery script, i installed it both in the js folder and in a js folder found in my theme

the website from i downloaded the file says to use this code:

<img src=”image.jpg” class=”ro” />
<input type=”image” src=”image.jpg” class=”ro” />

it says to put it in the image code, but where exactly do i put it in, in previous attempts it just shows up as 2 sequential images