Review here using Notes 853 and Notes 901 showed: Click on attach, select View, and "Magnify" was available on context menu. We tried number of examples, and all looked positive.
Is it possible that the result you are witnessing is specific to the attachment itself, ie Media file vs jpg or bmp? Are these embedded pictures/images or physical attachments, and can you reproduce on certain emails from external internet senders or from simply attaching a picture saved from internet locally on os desktop and attaching to a memo and saving it as a draft and opening that draft memo and attempting to View that attachment?
Since this is not reproducible in basic functioning to us at the moment, what we could advise is that if you do have a reproducible scenario and example, review the questions above, open a pmr with us and provide us with an example email and attachment content to take a look at for you along with steps you used to reproduce the issue, and we can take a more direct review of this case for you for further feedback.