Image base classing missing properties

Please be so kind and advise:

Dim MyImage As Aspose.Imaging.Image = Nothing

Based on the source file type, ie dng:
MyImage = TryCast(Image.Load(MyFileStream, LoadOpt), FileFormats.Dng.DngImage)
or tiff:
MyImage = TryCast(Image.Load(MyFileStream, LoadOpt), FileFormats.Tiff.TiffImage)

The problem’s here:
If source format is Tiff:

MyImage.XmpData = Nothing
For Each MyFrame As FileFormats.Tiff.TiffFrame In MyImage.Frames

XmpData is not a member of Aspose.Imaging.Image
Frames is not a member of Aspose.Imaging.Image

The base class image must have all shared properties otherwise seems useless and we’ll have to explicitly define each image class having longer and more complex work!
Am I right or there’s some workaround I’m missing?
Thanks. , let us process your request. You will be answered shortly! ,
the thing is than you declare MyImage var of Image type, while XmpData property belongs to RasterImage class.
Moreover, Frames property belongs to TiffImage class, while there is RasterCachedMultipage.Pages property for all multipage formats including TIFF format.
I am recommending you to declare variables in place with a necessary cast.
Hope this helps!