When I sort files by type in Files, both JPEG and TIFF file types are described unhelpfully as "Image". This oversimplification makes sorting effectively useless for me:
When writing this question I considered illustrating the unhelpfulness of such simplifications by joking that we might as well just use "Document" as a file type, an absurd notion when you imagine what sorting by type in the "Documents" folder might look like. You'll never guess what I found.
How can I stop this foolish behavior?
If you enable the MIME Type column then you should be able to distinguish between the different file types. Go to Edit -> Preferences then select the Columns List tab to add the MIME Type column.