Shaders themselves usually are less than 5K bytes - tiny. The images (texture files) they use can be big but you need those for most products regardless of whether you use them with shaders or just stick them straight onto the item.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)