Front :
<Image Name="camImage"/>
Back:
public async void Base64ToImage(string base64String)
{
// read stream
var bytes = Convert.FromBase64String(base64String);
var image = bytes.AsBuffer().AsStream().AsRandomAccessStream();
// decode image
var decoder = await BitmapDecoder.CreateAsync(image);
image.Seek(0);
// create bitmap
var output = new WriteableBitmap((int)decoder.PixelHeight, (int)decoder.PixelWidth);
await output.SetSourceAsync(image);
camImage.Source = output;
}