Core Image, in simple terms, puts the power of Photoshop and particularly Photoshop filters into the hands of the average developer. By building a generic suite for working with images, Apple has hugely simplified the way in which we can work with image data. The base of Core Image is a flexible image loading and storage mechanism that allows developers to write software that works with multiple bit depth images. This eliminates the need to worry about working with an 1-bit pixel, 8-bit or even 32-bit per pixel image; Core Image does the hard work for you.
Core Image then builds on this by providing a plug-in architecture called Image Units. Image Units can crop, rotate and otherwise filter the content of the images you are processing. You can even create new filters based on collections of other filters (like running a number of Photoshop filters simultaneously, or sequentially) and you can do all of this at a programming level, making developing software that works with images significantly easier. If the supplied filters aren’t good enough for you, you can also develop your own.
This opens up a whole range of possibilities beyond the usual approach of opening and image and working on it. As a developer you could, quite easily, develop a new droplet to automatically convert or translate an image into another format. A little bit more work (using Folder Actions) and you could make it do this automatically when you drop something on a folder.
But what does this mean for your average joe? Well, the simpler sequences where we’ve needed Photoshop (or GraphicConverter, or similar) may be a thing of the past. I doubt it will wipe out Photoshop; it’s a still a great compositing and image generation tool, as well as one use for manipulating and filtering image content. Photoshop also has a huge range of supplied and third-party plug-ins that will be difficult to beat.
Core Image is part of Tiger, which we all hope will be out soon (I’m betting on a WWDC launch). If you want more info on Core Image and what it can do, check out this great article on Apple’s Developer site.