SafeInCloud can automatically download icons for your website-related cards. For this feature to work a card must have a Website field with some valid website address in it. Then SafeInCloud will try to download a favicon from this website address.
Note, that not all websites have a correct favicon. Hence in some cases SafeInCloud might fail getting a website icon. You may try to force re-downloading by clicking the card's icon and selecting Use Website Icon. You can also force re-downloading for all cards at once by selecting Settings > Preferences > Website icons > Clear cache.
There also can be differences in downloaded website icons on a computer and a mobile device, because some websites automatically detect your device and provide different favicons.