Sup every1, i'm wondering if there is a plugin, or perhaps some free standing application, that lets you use an entire image as convolution matrix? Or at least some images to demonstrate what the result of this might look like? I'm especially interested in using an image to convolute itself, but combining different images may give good results too. If there isn't one already, this would be a really good thing for someone here with plugin programming skills to try.....

Do you mean using a kernel like this filter?
Filters → Generic → Convolution Matrix.
8.2. Convolution Matrix

Yeah, but with an entire image as the matrix, instead of a 5x5 set of pixels...

G'MIC has more options, Contours / Convolve.

No idea what you're talking about at all, don't think that has anything to do with it.

G'MIC is a must have plug-in for Gimp.

G'MIC convole info
Command line and GUI in Gimp.

The proper way to convolve an image with a big convolution kernel (here another image) is to perform a multiplication in the Fourier domain.
Implementing the direct convolution formula take ages otherwise (indeed, complexity of the explicit convolution is O(w*h*wk*hk)), where w,h is the size of your image and wk,hk the size of the convolution kernel.
There is one command in G'MIC that computes the convolution between two images, through the Fourier transform, but no filters for the plug-in for GIMP that uses this command actually.
It usually doesn't give very interesting results (from an artistic point of view). Below are some examples of convolutions of an image with another images.
The results have been normalized in [0-255] to make them visible.

Okay, so what would i need to perform this myself?

Do you have GMIC installed?

1. Install the G'MIC plug-in for GIMP.
2. Open two images as two different layers.
3. Open G'MIC dialog, press the 'Update filters' button.
4. Go to 'Testing / Ronounours / Convolve fft'.
5. Select 'Input Layers' -> 'All'.
6. Click 'OK', you should get your convolved result.

It's not there... i find a bunch of others under "Ronounours" but not that particular ones..... is there no simple convolution utility that doesn't use FFT though?

the new filter is working after the refresh button in Gmic

Well, that took a lot of work, but i've finally gotten some results out of this! There is definitely a lot to improve here, both in result and the rather cumbersome process, and while my attempt to do it with various photos turned out rather disappointing, these pictures should be enough to prove that there is real potential to be found here.

Wondering what the source images were? To paraphrase an old song.... your guess is just as good as mine, and probably the same!

No more comments?

Alright, i've finally started to grasp how to get any useful results of this. There's still a lot of things to be improved, and i discovered another way to get the same effect without using this plugin at all, but for now i won't go through all of it. The effects are esoteric to say the least, but at least some seem to be pretty much what i've been looking for. I'm not sure anyone here is even interested at all, but i could detail exactly how i made these images if you are curious. Here's some examples:





















And here's the full set of pictures i've made so far.... over 100 pics in two days!

http://www.mediafire.com/download/6dozui86skcrhnu

Giving this one last bump, to see if anyone wants to know how i made these pics...

Obviously not.

Obviously not.

There is no sense of being rude. That won't get you anywhere.
There are not too many people on line right now if you care to look. If you use some patience I am sure someone will be very interested in what you are doing, and would very likely want to see how you did them.