I have observed the image shared by you and like to share that whether images is of 547 MB. However, when it is loaded in using Aspose.Imaging it gets loaded in Document Object Model (DOM) of Aspose.Imaging and many statics are also initialized. So, it definitely takes more memory in Aspose.Imaging objects for obvious reasons. If you still feel that it is taking much more memory, you may share the source image, working sample project along with statistics with us. We shall, investigate that further on our end to help you out.
I have observed the sample code. However, as requested earlier, if you feel not agree to my explanation then provide us the source file that you are using and statistics achieved on your end in order to load that.