Using the code below, both Chrome and Opera (latest versions supporting border-radius) on Mac show a small blue area outside the rounded corners (which seems to a part of the defined background-image). Why?
<!doctype html>
<head>
<title>Testcase for rounded corners on submit button with bg-image</title>
<style type="text/css">
input[type="submit"] { background: url(http://skriblerier.net/div/rounded-corners-input/bg-bottom.png); color: #fff; height: 40px; width: 150px; border-radius: 10px; border: 1px solid #fff; font-size: 14px }
</style>
</head>
<body>
<form>
<div><input type="submit" /></div>
</form>
</body>