add thumbnail loader for TIFF images
Submitted by Sven Neumann
Link to original bug (#158192)
Description
A recent addition to the GIMP 2.2 API allows plug-ins to register an additional procedure to give access to a thumbnail embedded in an image file. The TIFF format allows for such thumbnails so it would be nice if the TIFF plug-in would provide this functionality.
Version: 2.1.x