Tiff files have special handling for importing.
Like all files, we upload the original, but create an (optional) optimised PNG, and (mandatory) thumbnail JPEG version for use in the UI.
For TIFF files, these pngs derive from the first image file extracted by
ImageMagick. The convert function will extract a file of the
specified type (PNG in our case), which, in a file named xxx.tif will be
xxx.png.
However, there is additional complexity with tiff files which contain layered
content. Specifically, the layer files will explode as xxx-n.jpg or
xxx-n.png where n is a numeric index.
Our code looks for this special case (see ImageOperations.checkForOutputFileChange)
and simply moves the -n layer file to the expected location.