Alright, Apple said there was a new remarkable feature related to the trash in the new El Capitan. However, what a poor design for such a good new function image!
It is impossible to change and replace the trash icon if you not in Recovery mode.
Step 1: Get OS X 10.11 Recovery boot by keep holding ⌘ and r after press the power button. And then you will be able to launch Terminal.
Step 2: Enter following command lines: csrutil disable
Of course, you can enable it after getting the job done by this “csrutil enable”
Step 3: Reboot your Mac by this command: reboot
Step 4: I am still using Mavericks. These above are the 4 image files (found in System/Library/CoreServices/Dock.app/Contents/Resources)
Step 5: You to reboot your mac to see the new design.