Gene – We’ve noted your request for this in one of our many other responses to you, but just to put our position on this out in the open I’ll also add it here.
Image generation is a very touch subject for us to tackle. We create a wide variety of caches, so pre-caching them would take some time. Each image has a total of 7 presets. Each preset has a proportional and cropped version in both standard and retina formats. That means that each image could potentially create 28 separate caches. Pre-caching after an upload of 30 images, for example, could take a lot of time and some or many of those caches may never be used, so it would mean wasted space and CPU cycles. On top of that, 95% of our users are on shared hosts, and kicking off a CPU intensive process like that over a long period of time could potentially get them in hot water with their host, ending up in an account suspension. So if we just place an option to turn that on, people are going to click it without knowing about the consequences (because why wouldn’t you want to turn that on?).
So our focus in the near-term is improving the speed of the on-demand image processing as much as possible. We implemented improvements for ImageMagick in 0.17.4 that cut some rendering times in half. Also, we are putting together an guide for those on dedicated servers to help them get the most of the ImageMagick, Imagick or GraphicsMagick, as they can all be tuned a bit further to improve speed. I’ll update this thread when we have that article up.
We very well may attempt to address pre-caching in the future via a plugin or in the app itself, but it’s a complicated issue and would take some consideration and testing.
Let me know if you have any other questions.