Okay... This is for DFB once she re-opens. It's a bigg'un so I'll understand if it's too complicated or whatever but here goes:
Banners -
Images (<- yeah, that's why it's big): Um, there's actually six, but they're not uber-detailed or anything so:
1,
2,
3,
4,
5,
6
Size: Normal sig height but wide enough to fit all six in side by side across the screen. (It doesn't matter if it's too wide for Serebii rules coz I'll probablly be using it on another forum.)
Style: Right, this is really picky but could it be green/grassy around the first one (sceptile), orange/fiery around the second (infernape), white/cloudy/feathery around the third (dodrio), blue/watery around the fourth (kabutops), purple/psychic glow type thing around the fith (gallade) and brown/earthy around the sixth (Marowak).
Text: None.
If it's going to be massively huge/you can't fit them all in, then just use the head and shoulders section of each one instead.
Again, sorry about the nit-picky specificness, tell me if it's beyond your capabilities.