regex101: background:url

Regular Expression

url(\((['\" ])*(?!data:|https?:\/\/)([^\"'\)]+)['\" ]*)

New

.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(http://instantcms.ru/templates/_default_/images/nyromodal/close.gif) no-repeat 6px center;
}

.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(https://instant/templates/_default_/images/nyromodal/close.gif);
}
.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url("../instant/templates/_default_/images/nyromodal/close.gif");
}
background:url(data:jpg;base64,/9j/4AAQSkZJRgABAQEASABIAAD/2wBDAAQDAwMDAwQDAwQFBAMEBQcFBAQFBwgGBgcGBggKCAgICAgICggKCgsKCggNDQ4ODQ0SEhISEhQUFBQUFBQUFBT/2wBDAQUFBQgHCA8KCg8SDwwPEhYVFRUVFhYUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBT/wAARCAApACADAREAAhEBAxEB/8QAFwABAQEBAAAAAAAAAAAAAAAAAAQDBv/EABgQAQEBAQEAAAAAAAAAAAAAAAAScRNh/8QAFwEBAQEBAAAAAAAAAAAAAAAAAAECBv/EABQRAQAAAAAAAAAAAAAAAAAAAAD/2gAMAwEAAhEDEQA/AOQvHYOWLwC8AvAT3jKl4BeAXgMKFKAoCgTdBToB0A6Amv1Gi/QL9Av0GaqAAA//2Q==)

Extraction

.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(http://instantcms.ru/templates/_default_/images/nyromodal/close.gif) no-repeat 6px center;
}

.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(https://instant/templates/_default_/images/nyromodal/close.gif);
}
.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url("../instant/templates/_default_/images/nyromodal/close.gif");
}
background:url(data:jpg;base64,/9j/4AAQSkZJRgABAQEASABIAAD/2wBDAAQDAwMDAwQDAwQFBAMEBQcFBAQFBwgGBgcGBggKCAgICAgICggKCgsKCggNDQ4ODQ0SEhISEhQUFBQUFBQUFBT/2wBDAQUFBQgHCA8KCg8SDwwPEhYVFRUVFhYUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBT/wAARCAApACADAREAAhEBAxEB/8QAFwABAQEBAAAAAAAAAAAAAAAAAAQDBv/EABgQAQEBAQEAAAAAAAAAAAAAAAAScRNh/8QAFwEBAQEBAAAAAAAAAAAAAAAAAAECBv/EABQRAQAAAAAAAAAAAAAAAAAAAAD/2gAMAwEAAhEDEQA/AOQvHYOWLwC8AvAT3jKl4BeAXgMKFKAoCgTdBToB0A6Amv1Gi/QL9Av0GaqAAA//2Q==)