I guys,
I try couple things around but I still not able to modify a bitmap image as I want In Grasshopper.
I want to extract all the Green colors of that image and turn it to white and what’s left in black…
I know that Firfly plugin have a «decompose image component». but I can’t achive anything with it… So far I don’t know other plugin that can do something to modify images…
Thanks 
Charles C.
It‘s no real answer on your question.
But it‘s might possible for you to use Photoshop? Would be much faster/easier and you still can insert them to grasshopper after.
A great Thanks once again Kim !! This is exactly what I was looking for. So I don’T have to do all these manipulations into photoshop !
I don’t know you can simply write «white» and add a color swatch to find a specific color !
I still have one question: how could I set a «range» of color instead of one color swatch ??? The thing is I want to select only the trees… But its quite difficult…
Yes I know photoshop could be a solution, but In the definition I’m trying to make, I use many bitmap… and Its a longer process to edit them in psd then import it back into Grasshopper. I try to automate this task 
You can always use Macros in photoshop, apply the same set of commands to every bitmap. Photographers don’t actually edit every one of their 1000 photos one by one.
Yes I do have batch script in photoshop. But going googlemap -» photoshop -» grass -» flowdesign -» photoshop -» grass -» etc is sometimes a long process… I thought I could manage it differently with grasshopper…
However the grasshopper bitmap manipulation is heavy with firefly… I think I will have to go old school method !
