I explained here Save picture size
I simply do:
MyMemoryBlockA = MyPictureA.ToData(MyPictureFormat, Picture.QualityMaximum)
I have a original picture I resize in MyPictureA.
MyMemoryBlockB contains the binarystream of the folderitem (picture) which is already in my target folder. And I do:
MyPictureB = Picture.FromData(MyMemoryBlockB)
If the size (width height) of picture A and B are the same I compare the two MemoryBlock A and B.
If the picture are the same then I don’t save the new one, if different I replace the picture in the Target folder by the one I just resized.
This is a single command line to make a picture from MemoryBlock or vice versa then I don’t think there is anything to optimise.