斯威夫特5号，Xcode 10号。

let imageData = UIImage（named：“imagename”）.pngData（）？.base64EncodedString（选项： .lineLength64Characters） 打印（图像数据）

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!

}

在swift 2.0中使用此扩展(credit to Jonas Franz)

extension UIImage{
  func toBase64() -> String{
    let imageData = UIImagePNGRepresentation(self)!
    return imageData.base64EncodedStringWithOptions(.Encoding64CharacterLineLength)
  }
}

很好理解你是否传递了Tyler Sheaffer所说的前缀。 但出于某种原因，你可能需要这个前缀来描述base64字符串开头的mime类型，所以我建议这段代码在编码之前传递一些选项(Swift 5):

extension UIImage {

    enum Format: String {
        case png = "png"
        case jpeg = "jpeg"
    }

    func toBase64(type: Format = .jpeg, quality: CGFloat = 1, addMimePrefix: Bool = false) -> String? {
        let imageData: Data?
        switch type {
        case .jpeg: imageData = jpegData(compressionQuality: quality)
        case .png:  imageData = pngData()
        }
        guard let data = imageData else { return nil }

        let base64 = data.base64EncodedString(options: Data.Base64EncodingOptions.lineLength64Characters)

        var result = base64
        if addMimePrefix {
            let prefix = "data:image/\(type.rawValue);base64,"
            result = prefix + base64
        }
        return result
    }
}

对于Base64代码，例如:

"data:image/jpg;base64,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"

使用Swift5.0代码如下:

func imageFromBase64(_ base64: String) -> UIImage? {
    if let url = URL(string: base64), let data = try? Data(contentsOf: url) {
        return UIImage(data: data)
    }
    return nil
}

斯威夫特5。

class ImageConverter {

    func base64ToImage(_ base64String: String) -> UIImage? {
        guard let imageData = Data(base64Encoded: base64String) else { return nil }
        return UIImage(data: imageData)
    }

    func imageToBase64(_ image: UIImage) -> String? {
        return image.jpegData(compressionQuality: 1)?.base64EncodedString()
    }

}