The MS documentation on FILESTREAM makes it sound like it should only be used for archiving unstructured data. Am I misunderstanding this?
Your understanding of the feature is correct.


  It just sounds like the FILESTREAM option is more for archiving files (or unstructured data) that once it's saved, should really only be referenced through read operations.


Yes. However, you're welcome to perform updates and deletes, keeping in mind that it can have a negative effect on performance.

For your use case, with small files of around 1 MB in size, you probably won't run into the issue as quickly.

You can also check out FileTable, which exposes an SMB share via FILESTREAM, if you're going to be doing modifications to the images.