Why aren't all my payment icons appearing in the footer?
Confirm that all the preferred payment types are set up correctly in the Shopify admin (Settings > Payments)
Check the Show payment icons configuration to make sure it is checked/enabled in the theme editor Footer section (Customize > Footer)
Compare your theme version/release number to the Release notes to see if the icons have been added since your version. To find your Grid theme's version number, navigate to the theme editor (Customize), then select Theme settings—it should be visible at the bottom left of the left side-bar: