5 Easy steps for making camouflage mosaic decal.
Step 1. Find a normal camouflage images
Step 2. Make it black and white in Photoshop or other photo editor.
Step 3. Convert the image to mosaic from "Filter->Pixel->Mosaic".
Step 4. Trace the image in Illustrator, may set to 5~6 color.
Step 5. Copy and paste from the traced image and make what you want like the pattern below.