No huger task than it was to create them in the first place, hopefully.
There will be two modes of operation, one exports the raw, paletted textures used, so you can edit those and still stay compatible with the original data format.
These can then be re-imported and will work just fine in unmodified 1.02
The other option will be to export the entire scene as a number of images, each representing different animation states. These can then be filtered, resized or whatever and when you re-import them, the application will create replacement textures for use with the OpenGL driver (version 0.7b). The kicker here of course is that there are no restrictions in size or color depth.
Later on I may very well add the ability to create entirely new backgrounds and allow you to completely redefine the animations as you see fit, but the primary goal is to be able to replace existing backgrounds with higher-quality versions.