// 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; } }