在Swift 3.0和Xcode 8.0

编码:

let userImage:UIImage = UIImage(named: "Your-Image_name")!
let imageData:NSData = UIImagePNGRepresentation(userImage)! as NSData
let dataImage = imageData.base64EncodedString(options: .lineLength64Characters)

解码:

let imageData = dataImage
let dataDecode:NSData = NSData(base64Encoded: imageData!, options:.ignoreUnknownCharacters)!
let avatarImage:UIImage = UIImage(data: dataDecode as Data)!
yourImageView.image = avatarImage

在Swift 3.0中

func decodeBase64(toImage strEncodeData: String) -> UIImage {

    let dataDecoded  = NSData(base64Encoded: strEncodeData, options: NSData.Base64DecodingOptions.ignoreUnknownCharacters)!
    let image = UIImage(data: dataDecoded as Data)
    return image!

}

斯威夫特3.0

将图像转换为base64字符串

操场测试

    var logo = UIImage(named: "image_logo")
    let imageData:Data =  UIImagePNGRepresentation(logo)
    let base64String = imageData.base64EncodedString()
    print(base64String)

我尝试了所有的解决方案，没有一个对我有效(使用Swift 4)，这是对我有效的解决方案，如果将来有人面临同样的问题。

let temp = base64String.components(separatedBy: ",")
let dataDecoded : Data = Data(base64Encoded: temp[1], options: 
 .ignoreUnknownCharacters)!
let decodedimage = UIImage(data: dataDecoded)

yourImage.image = decodedimage

4.2扩展方法

extension UIImage {
    func toBase64() -> String? {
        guard let imageData = self.pngData() else { return nil }
        return imageData.base64EncodedString(options: .lineLength64Characters)
    }
}

XCode 9.1和Swift 4.0

//
// Convert UIImage to a base64 representation
//
class func convertImageToBase64(image: UIImage) -> String {
    let imageData = UIImagePNGRepresentation(image)!
    return imageData.base64EncodedString(options: Data.Base64EncodingOptions.lineLength64Characters)
}

//
// Convert a base64 representation to a UIImage
//
class func convertBase64ToImage(imageString: String) -> UIImage {
    let imageData = Data(base64Encoded: imageString, options: Data.Base64DecodingOptions.ignoreUnknownCharacters)!
    return UIImage(data: imageData)!
}

Swift 4.2 | Xcode 10

extension UIImage {

    /// EZSE: Returns base64 string
    public var base64: String {
        return self.jpegData(compressionQuality: 1.0)!.base64EncodedString()
    }
}