You’ll need to download the .ICO file for the image you need.
For example, if you have a shortcut to a website but you want to change the shortcut image to a Solitaire Icon instead of the Google Chrome Icon then you’ll go online and search: Solitaire .ICO download.
You’ll be looking for something like this:
https://www.iconfinder.com/icons/71473/solitaire_icon
Once you have your image downloaded, right click the shortcut you’re trying to change and select Properties > Select the Shortcut Tab > Change Icon.
If your image isn’t on that pop up by default then select “Browse” and look for the image you downloaded.
Select file and hit OK twice to save the settings.