Did you upload that image in Shopify first? The invalid url input means you are not correctly adding the image url on the section.
Add you image in Files section under settings. Once uploaded, Shopify will give you a url. Then you can paste that url on that section.
Alternatively, you can upload the image you want directly on that section.
If this is still an issue, please DM me your store code for me to check and solve that for you.
