Option to show custom icon instead of Pushover icon on Apple Watch notifications

I am curious if it would be possible to show a higher-resolution custom icon instead of the Pushover icon for alerts that have a custom icon. I already know it's Pushover - but at a glance it would be cool to see a custom icon of my choosing when the alert initially comes through instead of having to tap into it. 

The current limitation on size for the custom icon is too small for this as it already shows up very pixelated when viewed on the watch, but maybe there's some sort of caching that could be done for a larger icon.