You can configure Media Settings as you like. Go to Business Settings > Media Settings.
Placeholder Image: In this section, you can set a media placeholder image.
Enable/Disable Watermark: In this section, you can enable or disable on watermark image.
Watermark Image: In this section, you can set the watermark image.
Watermark Image Position: In this section, you can set the watermark image position.
Watermark Image opacity(%): In this section, you can set watermark image opacity in %.