I know how that feels!
You can ask the mods to upload one avatar per month that you'll actually be using, so you can't ask them to upload a bunch unfortunately.
You mail the picture to
portraits@rpol.net and add your username (or else it won't get added). They upload new pictures once a month, around the 27th.
You can find more info here:
/help/?t=faqs&page=portraitsfaq
I've found that it's best to send the image in the right size yourself. I once sent a bigger one and they compressed it and it became really blurry.