If you are thinking you are finally able to ditch Apple Podcasts, here are a few quick facts about the iOS version of the Google Podcasts app that you'll want to check out first.
To change icons in macOS, copy the new icon or image, right-click on the folder or file you want to change, select Get Info and paste the new icon or image.
One way the images could be extracted from the .webarchive file is through the Terminal app. Here's how.1 - Press Command and space to launch Spotlight, type in "Terminal" and hit Enter. That'll open the Terminal app.2 - Type in this command without hitting Enter. Note there is a space at the end after "html". textutil -convert html3 - Drag the .webarchive file into Terminal. Hit Enter and you'll find all the extracted files in the same folder where the .webarchive file is located.