Hi-res is going to be a relative term here. For use as an icon (usually something meant to be smaller), or an avatar, these would be considered hi-res since those things are meant to be about 100x100 pixels, and at that size, these were made to be clear and visible. What's in game and currently exists seems to be built for 32x32.
Something like a background image would need to be anywhere from 1080 to 4K resolution. Making power icons that large would have taken up a lot of space. Fortunately for you, the AT icons we made in vector art, so it's quite easy to scale up. I'll send you a Sentinel icon at 1080. 🙂