Image.getSize is unnecessarily decoding image which is causing an high memory bump (which will be garbage collected in the future)

Reproduce (the specific url is used to show a big size image example) :

 Image.getSize("https://www.nasa.gov/sites/default/files/thumbnails/image/oct_1_2015_flare.jpg",
      (width,height)=>{
            //code
      }
)

The above example is causing memory bump of approximately 50MB.
In think that using encoded image instead of decoded image is the right approach.

I will add a pull request - change the implementation to use encoded image.