How to create a sprite sheet for a simple frame based animation
A simple frame based animation can be achieved by placing each frame into a separate layer, and then exporting all layers and combining them into a sprite sheet. Use the 'paste in place' option when copying your drawing to a new layer to make sure the layers are aligned properly.
To make the export easier, you can make use of the JettyInk extension (shipped by default). Choose 'Save a copy' and then 'JessyInk zipped pdf or png output' from the dropdown list. Choose png and whatever resolution you want. This will give you a zip-file that contains each layer as a separate png image.
The following command line instructions will then create a sprite sheet of your animation:
unzip name.zip convert Frame*.png +append name_spritesheet.png
Note 1: This assumes that each layer has been labeled Frame01, Frame02 etc.
Note 2: You need the command 'convert', which is part of imagemagick.