var values = [UInt8] (повторяется: 0, count: imgData.count)
imgData.copyBytes (to: & amp; values, count: 1)
switch values {
case 0xff:
return "image/jpeg"
case 0x89:
return "image/png"
case 0x47:
return "image/gif"
case 0x49, 0x4d:
return "image/tiff"
}
return ""