Computer Configuration > Administrative Templates > Microsoft Edge > Content settings
Both
HKLM\Software\Policies\Microsoft\Edge
Define a list of sites, based on URL patterns, that can display images. If you don't configure this policy, the global default value is used for all sites either from the 'DefaultImagesSetting' (Default images setting) policy (if set) or the user's personal configuration. For detailed information about valid url patterns, see https://go.microsoft.com/fwlink/?linkid=2095322. Wildcards (*) are allowed. Example value: https://www.contoso.com [*.]contoso.edu