To simplify the work of animating my cartoon about a mouse, a plug-in for the GIMP raster editor has been written, to allow the direct exporting of multi-layered images to corresponding layers of the 2D animation package Synfig.
The plug-in registers itself in the GIMP image menu <image> > File > Export > Synfig.
There are export options you can choose. If the field "output path" is empty, the synfig canvas will be kept in the same directory as the initial picture.
Here is the result:
At the top you can see the initial image in Gimp, and at the bottom the same image imported into Synfig.
You can download the synfigexport plugin here.
To make it work, gimp must support Python, and the most recent version of Python must be installed on your computer.
To install this plug-in, simply put the file in ~/.gimp-*/plug-ins/ and make it executable (chmod +x synfigexport.py), then restart gimp.
This program is licensed under Creative Commons Attribution 3.0 Unported License. Distribution and updating of the code is appreciated.