Base64 encoding in Swift will not decode in Android

I have an Android app which uses Base64 to encode images, and encoded strings are stored on a server. I am now making an iOS client for the same app and am struggling to make it encode images in the same way
Images encoded on the android end will decode in Swift iOS but images encoded in Swift will NOT decode in Android, or here (the resulting file isn’t a valid image)

Images encoded in iOS WILL decode in iOS

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  • In Android, I am using the following to encode and decode

    public static String encodeBitmap(Bitmap bitmap) {
        Bitmap immagex = bitmap;
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        immagex.compress(Bitmap.CompressFormat.PNG, 100, baos);
        byte[] b = baos.toByteArray();
        String imageEncoded = Base64.encodeToString(b, Base64.DEFAULT);
        return imageEncoded;
    public static Bitmap decodeBitmap(String encodedString) {
        byte[] decodedByte = Base64.decode(encodedString, Base64.DEFAULT);
        Bitmap b = BitmapFactory.decodeByteArray(decodedByte, 0,
        return b;

    And the following on the iOS side

    static func decodeImage(str: String) -> UIImage?{
        if let decodedData = NSData(base64EncodedString: str, options: NSDataBase64DecodingOptions.IgnoreUnknownCharacters){
            var iconValue:UIImage? = UIImage(data: decodedData)
            return iconValue
        return nil
    static func encodeImage(image: UIImage) -> String{
        var imageData = UIImagePNGRepresentation(image)
        let base64 = imageData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.Encoding76CharacterLineLength)
        return base64


    I am willing to change either client to make it work

    take this image for example

    On Android it encodes to

    And on iOS to

    iOS one has a much larger character count

    Solutions Collect From Internet About “Base64 encoding in Swift will not decode in Android”

    The Base64 provoided are from different PNG encodings. The headers are different, Android has a “sBIT” chunk and iOS has a “sRGB” chunk.

    Thus the problem is not Base64 but the representatins prpovided by the two systems.

    Decoded portions