OpenSlide Only Recognizing Topmost Layer

[jcupitt at gmail.com]

> 2) Isn't the convert bundled with VIPS actually a copy of the  ImageMagick utility (with the ptif bugs fixed)?

VIPS has it's own pyramid builder, it's part of the tiff writer
("tiffsave" in those timings I pasted). In fact it has two: one for
pyramidal tiffs and one for deepzoom/zoomify/google maps directory
trees.

The Windows binary includes a build of imagemagick which vips will use
to import formats like GIF.

John