Does Colorbox create any cached images? It doesn't appear that it creates any permanently cached files like cachemanager does for the rest of the gallery. I'm guessing that there is no way to pre-cache for colorboax since colorbox has no way of knowing every conceivable viewers screen size in advance. Just wondering if there is any way to speed up the load time of colorbox images.

Normally the colorbox calls the full images directly without any processing if enabled and just fake resizes the image to fit its setting. In no standard theme there are any sizing settings.

The only way it would cache is if you setup the protected image view then the full image is served by a script and therefore cached. But as with all caches that should happen only once.