I have drawn an icon in Inkscape, but would now like to programmatically alter it (change the colours slightly for different icon states) and convert it to a tiled PNG format file containing multiple icons with different colours. I know about Inkscape’s –export-png options, but can’t see a way to make it change the image and/or export multiple times to different parts of the combined image.
Are there any good user-oriented tools for programmatically fiddling with images, or do I have to delve into GD or even manually modifying the SVG XML?
Even though I’m not 100% sure if it fulfills your request for user-orientation, I recommend you to have a look at http://www.imagemagick.org. I have successfully used its ‘convert’ utility for scripting conversion from svg to png and also for adding custom background colors.