Computer Configuration > Administrative Templates > Microsoft Edge > Content settings
Both
HKLM\Software\Policies\Microsoft\Edge
Define a list of sites, based on URL patterns, that aren't allowed to display images. If you don't configure this policy, the global default value from the 'DefaultImagesSetting' (Default images setting) policy (if set) or the user's personal configuration is used for all sites. 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