// This function is used to detect the actual image type, 
function getMimeType(file, fallback = null) {
	const byteArray = (new Uint8Array(file)).subarray(0, 4);
    let header = '';
    for (let i = 0; i < byteArray.length; i++) {
       header += byteArray[i].toString(16);
    }
	switch (header) {
        case "89504e47":
            return "image/png";
        case "47494638":
            return "image/gif";
        case "ffd8ffe0":
        case "ffd8ffe1":
        case "ffd8ffe2":
        case "ffd8ffe3":
        case "ffd8ffe8":
            return "image/jpeg";
        default:
            return fallback;
    }
}