extensions/emmet/src/imageSizeHelper.ts/sizeForFileName
function sizeForFileName(fileName: string, size?: ISizeCalculationResult): ImageInfoWithScale | undefined {
	const m = fileName.match(/@(\d+)x\./);
	const scale = m ? +m[1] : 1;

	if (!size || !size.width || !size.height) {
		return;
	}

	return {
		realWidth: size.width,
		realHeight: size.height,
		width: Math.floor(size.width / scale),
		height: Math.floor(size.height / scale)
	};
}