To be specific: I have used GraphicsGale for pixel art sprites. The program saves its files in its own format (.gal, I believe), but the images in my game have to be .png. Saving it to .png loses information for GraphicsGale, like the palette. Manually keeping to seperate files impairs the workflow. Ideal would be that after every save, the original file is saved in one folder, and a .png export in another, awaiting runtime and packing. Any suggestion/thoughts?
Automation is a common solution here. Create a build script that checks the date/time of source assets and automatically exports fresh game assets for the files that are out of date.
The details of the script will vary depending on the content creation tools, and the type of assets. Some of them can be easily automated with command line calls to their executables along with some input parameters (i.e. . With others you might have to get more creative and use GUI automation tools like Autoit.
Many IDEs will allow for custom scripts to be run before or after their own build process. Check your own IDE to see if such a thing is allowed, if not, you might check to see if you can include the building of your project in the automation (might want to do that anyway, just to have a complete solution).
This automation process should be made to be fairly flexible. For example, you don't want to have to explicitly include each source asset file you create. Make the script recognize file extensions to decide how to handle the file. Also, organizing your source asset directory the same way your game asset directory is organized will help the script automatically place generated files where they're supposed to go.