As a pro Wix Website Designer, I get this question a lot. Is your Wix Facebook Share Image not Updating?
Here's the solution, make sure that your new Wix Social Share image is updated and the site is Published with the changes, then use the Facebook Debugger to get Facebook to "Scrape Again" to get the new image uploaded. Use an image with 16 x 9 dimensions (1600 x 900 pixels wide works best).
Make sure to hit "Scrape Again" multiple times until you see it update, it usually takes me 3-5 times of hitting "Scrape Again" for it to refresh here for some reason. See video below for more tips.
Not sure where to add a Social Share image in your Wix website? Each page has it's own Social Share image you can setup if desired, here is where to find it in the Wix tutorial video below: