This is an interesting effect. I have tried to duplicate it over the last several days without success. It would be great if you would post a tutorial including how you got the brick wall background.
You need to have a movie brush with different pictures of brick walls. The folder of images i used to make the movie brush i used for this image are all graffiti images i shot with a digital camera in various dingy alleyways in SOMA in San Francisco. This particular set had a lot of images of graffiti paint patterns on brick walls. If you just wanted to you could use a folder of images of brick walls or concrete walls, or whatever sets of images you want for their textural qualities. I've done series of photo mosaics where all the images are metal garage door patterns, or distressed wood fragments, or trash pictures from the dump, or close up shots of pebbles, or close up shots of plants in nature. I tend to go for a hard industrial look in a lot of my personal work but if you choose nature or some other form of pleasant or organic imagery you would get a totally different feel from the photo mosaics.
I'm using the Adaptive Block DM path start generator for these. The DM options are new in version 4 and split the blocks to better represent the source image. So you would have to use the adaptive block path start generator in 3.5. I'm using region as brush pen mode for these. The trick to using this pen mode for photo mosaics is to use the region as brush generated region to be the alpha channel for the source brush since you don't want to overdraw the movie frames in the source movie brush. You do this by setting the Brush Option control in the Region as Brush Mode control panel to Alpha Only. You also need to make sure the PathStart Regionize control in there is turned on when using this pen mode with path start regionization for best results.
I'm colorizing the movie frames as they are laid down to match the computed source color. I do this by filling from the Brush Load, using an image processing brush load, and using an algorithm for the brush load that colorizes the images (like Paint Color Men Shift).
Comments
I'm using the Adaptive Block DM path start generator for these. The DM options are new in version 4 and split the blocks to better represent the source image. So you would have to use the adaptive block path start generator in 3.5. I'm using region as brush pen mode for these. The trick to using this pen mode for photo mosaics is to use the region as brush generated region to be the alpha channel for the source brush since you don't want to overdraw the movie frames in the source movie brush. You do this by setting the Brush Option control in the Region as Brush Mode control panel to Alpha Only. You also need to make sure the PathStart Regionize control in there is turned on when using this pen mode with path start regionization for best results.
I'm colorizing the movie frames as they are laid down to match the computed source color. I do this by filling from the Brush Load, using an image processing brush load, and using an algorithm for the brush load that colorizes the images (like Paint Color Men Shift).