Multi-threaded / multi-cores resizing and encoding export operations
I often use GThumb (version 3.12.2) to select a couple hundreds of images and, with the "Tools" (wrench) toolbar icon, make lower resolution resized images (ex: HD instead of 12 MP). As revealed in issue #173 (closed), GThumb version 3.11.4 brought us multi-threaded thumbnails generation; however, this does not seem to be implemented for other processing-intensive tasks like batch resizing (I can see the equivalent of only one of my 8 cores being used while doing so, and the process takes a long time while my CPU is mostly under-utilized).
It would be fantastic to have multi-threaded resizing/encoding/processing for most/all batch operations in GThumb. Since multi-core processors have pretty much become the norm, this would make batch/export operations much faster in GThumb.