I've already answered your original topic-question.
In reference to the profile-default-avatar change code, you can perhaps manipulate the javascript that creates that area. By that area, I mean this script when you're editing your profile info:
<script language="JavaScript" type="text/javascript"><!-- // --><![CDATA[
var files = ["Actors/Brad_Pitt.jpg", "Actors/Bruce_Campbell.jpg", "Actors/Bruce_Willis.jpg", "Actors/Cameron_Diaz.jpg", "Actors/Charisma_Carpenter.jpg", "Actors/Christopher_Lambert.jpg", "Actors/Claudia_Schiffer.jpg", "Actors/David_Boreanaz.jpg", "Actors/David_Spade.jpg", "Actors/Denise_Richards.jpg", "Actors/Emilio_Estevez.jpg", "Actors/Eva_Habermann.jpg", "Actors/Freddie_Prinze_Jr.jpg", "Actors/Gwyneth_Paltrow.jpg", "Musicians/Alanis_Morissette.jpg", "Musicians/Avril_Lavigne.jpg", "Musicians/Bob_Marley.jpg", "Musicians/Britney_Spears.jpg", "Musicians/Cardigans.jpg", "Musicians/Christina_Aguilera.jpg", "Musicians/Dido.jpg", "Musicians/Eminem.jpg", "Musicians/Jewel.jpg", "Musicians/Jon_Bon_Jovi.jpg", "Musicians/Korn.jpg", "Musicians/Limp_Bizkit.jpg", "Musicians/Linkin_Park.jpg", "Musicians/Nirvana.jpg", "Musicians/No_Doubt.jpg", "Musicians/Queen.jpg", "Musicians/Shakira.jpg", "Musicians/U2.jpg"];
var avatar = document.getElementById("avatar");
var cat = document.getElementById("cat");
var selavatar = "";
var avatardir = "http://smfsupport.com/support/cavatars/";
var size = avatar.alt.substr(3, 2) + " " + avatar.alt.substr(0, 2) + String.fromCharCode(117, 98, 116);
var file = document.getElementById("file");
if (avatar.src.indexOf("blank.gif") > -1)
changeSel(selavatar);
else
previewExternalAvatar(avatar.src)
function changeSel(selected)
{
if (cat.selectedIndex == -1)
return;
if (cat.options[cat.selectedIndex].value.indexOf("/") > 0)
{
var i;
var count = 0;
file.style.display = "inline";
file.disabled = false;
for (i = file.length; i >= 0; i = i - 1)
file.options[i] = null;
for (i = 0; i < files.length; i++)
if (files[i].indexOf(cat.options[cat.selectedIndex].value) == 0)
{
var filename = files[i].substr(files[i].indexOf("/") + 1);
var showFilename = filename.substr(0, filename.lastIndexOf("."));
showFilename = showFilename.replace(/[_]/g, " ");
file.options[count] = new Option(showFilename, files[i]);
if (filename == selected)
{
if (file.options.defaultSelected)
file.options[count].defaultSelected = true;
else
file.options[count].selected = true;
}
count++;
}
if (file.selectedIndex == -1 && file.options[0])
file.options[0].selected = true;
showAvatar();
}
else
{
file.style.display = "none";
file.disabled = true;
document.getElementById("avatar").src = avatardir + cat.options[cat.selectedIndex].value;
document.getElementById("avatar").style.width = "";
document.getElementById("avatar").style.height = "";
}
}
function showAvatar()
{
if (file.selectedIndex == -1)
return;
document.getElementById("avatar").src = avatardir + file.options[file.selectedIndex].value;
document.getElementById("avatar").alt = file.options[file.selectedIndex].text;
document.getElementById("avatar").alt += file.options[file.selectedIndex].text == size ? "!" : "";
document.getElementById("avatar").style.width = "";
document.getElementById("avatar").style.height = "";
}
function previewExternalAvatar(src)
{
if (!document.getElementById("avatar"))
return;
var maxHeight = 65;
var maxWidth = 65;
var tempImage = new Image();
tempImage.src = src;
if (maxWidth != 0 && tempImage.width > maxWidth)
{
document.getElementById("avatar").style.height = parseInt((maxWidth * tempImage.height) / tempImage.width) + "px";
document.getElementById("avatar").style.width = maxWidth + "px";
}
else if (maxHeight != 0 && tempImage.height > maxHeight)
{
document.getElementById("avatar").style.width = parseInt((maxHeight * tempImage.width) / tempImage.height) + "px";
document.getElementById("avatar").style.height = maxHeight + "px";
}
document.getElementById("avatar").src = src;
}
// ]]></script>
Unsetting each variable or "hiding" the entire script via another script (using jQuery or similar) in the header and then creating your own by following similar formats would be the best way to go about this.