[feature request] Guide on custom C-Gear/Pokedexes?

[Camwoodstock]

Currently, the instructions provided for how to upload custom images for the C-Gear/Pokedex are... well, uh, basically non-existent. The only guides I can find online are for doing so via PKHex and another program called CGearpoke. The feature is there on Entralinked, and I am very curious about it! But I have no idea how to use it. Documentation is always handy, but it'd be especially useful for these, I'd wager.