Image related queries in PhoneGap

Image related queries in PhoneGap

I am about to begin a project in PhoneGap for Android, Windows Mobile and
BlackBerry.
There are some question I have:
where would I place Android images? In Titanium Studio we had folders for
ldpi/mdpi/hdpi images inside android/image/ folder, but in PhoneGap there
isn't such a folder.
how do I create a button from JavaScript with it's size being decided by
the image we assign it?
In my CSS:
.deleteButton {
background-color:Transparent;
background-image:url('../img/button_delete.png');
width:64px;
height:32px;
}
My JavaScript code to create button:
var element4 = document.createElement("input");
element4.type = "button";
element4.setAttribute("onclick","deleteSelectedRow(this)");
element4.className = "deleteButton";
cell4.appendChild(element4);