Image blender

Loading multiple input images was requested a lot of time ago. The major problem is that it doesn't work well with "filter as a black box" concept, which allows you to use filters on any kinds of images, including using Filter Forge as a plugin within compatible hosts. Also, you cannot reliably share filters that depend on external bitmaps. Technically, there's almost nothing that prevents Filter Forge from using multiple input images in a single filter (there is some work to do of course, but it shouldn't take much time), but as I told before, the problem belongs to the usage efficiency and consistency domain, instead of performance and implementation details one.
As a conclusion, I do not think that multiple images will be supported in near future. I myself would like to have the "External Image" component very much, but ...

james, what is "image resynthesis" ? and what does a "random splitter" do?

you could actually have unlimited image imports. that's not the problem, even when using FF in plug-in mode. FF could just use a default image component for that with the rest of the image components being labeled 'image 1', 'image 2' etc. that isnt the problem, james. the problem is your gray scale map image. that either has to be a standard image within FF or a standard editor within the main editor so that whatever you upload to the library can consistently be used by everyone that downloads it. it's the same thing as the lighting environments. uploads to the library have to use standard components so everyone can use them and you cant just upload anything and everything or you start running into major problems with copyrights and pirating.

if you left out the gray scale image mapper and just used other components, like the noise components, that would or could work, since those are standard, consistent items within FF.

getting a lot of stock images as a part of FF becomes very cumbersome and costly and even limiting and it's not a practical solution. sub-editors might work, though, where you've got a gray scale image mapping editor for an image mapping component. essentially, that's what a lot of the components already are, in a way. a perlin noise component is essentially a gray scale mapping component with sliders. the sliders and checkboxes are the 'sub-editor'.

and, believe it or not, there already exists a sort of work-around for importing multiple images at one time, though certainly not as elegant or efficient as having two or more images loaded at one time. you simply save your image that's been worked in FF and then load that back into FF as your imported image and work it again under new parameters. yeah, not really a great solution, but i've done it on some images.

the whole 'sub-editor' field is a wide open area yet to FF. a grey scale sub, an hdri sub and i'm sure there are several other possibilities as well, could all potentially exist within an FF type program. give me an airbrush tool, a color picker and a clean, blank field as a sub-editor and i could have some fun there's lots of un-tapped potential in FF yet. i'm sure we'll be seeing some interesting things coming down the road

oh, ok. well, you can do a lot of that with a threshold and set alpha and other combinations of components. even a blend component will do a lot of that. but, it wont do it on multiple imported images since we dont have that feature.

also, bear in mind that multi-imports is already on the list, i believe. see the wiki list.