Set Image Metadata node adds offsets to existing offsets instead of setting them

[imagejan]

When using the Set Image Metadata node to set offsets of an image that already contains offset information, the new offsets are added to the existing ones.
This behavior is unexpected and not well documented in the node dialog.

Here's an example workflow illustrating the issue:
Offset Bugs.zip

(I stumbled upon this because the Splitter node now respects image offsets, and my workaround now produces false image offsets, see closed issue #459 ;-)