Additional Custom Media Sizes

Hi all,

Looking in Admin > Settings > Media, I can see sizes for thumbnail, medium and large sizes, which I’ve modified to suit my requirements. Ideally, however, I’d like to define more sizes for other uses on my website.

I’ve defined 160×0, 320×0 and 960×0 as the wordpress-managed sizes, but I’d like to define other sizes for use on my homepage and section pages.

Here are the questions:

1. Are there any hooks are available for me to use in order to capture and process media once it’s been uploaded, so that I can create my own custom sizes?
2. Once processed and saved to the wp-content/uploads/… directory, will these sizes be picked up by any calls for the relevant sizes, using wp_get_attachment_image_src() for example.
3. Are there any plans for allowing users to set an arbitrary number of extra image sizes using the Admin > Settings > Media panel?
4. Are there any plugins that exist which would allow this? (If not, my plan is to write one.)

Thanks for your help!