VNC image local build error

Hey there, great images. I am having some issues building it locally.
```
Step 4/10 : ENV USER root
---> Running in 6b2c881d3107
---> 9c91f0c8818e
Removing intermediate container 6b2c881d3107
Step 5/10 : COPY password.txt .
---> 71f859bc9d2d
Removing intermediate container 7a7772cc3d2a
Step 6/10 : RUN cat password.txt password.txt | vncpasswd && rm password.txt
---> Running in 10ebdba5fef9
Using password file /root/.vnc/passwd
VNC directory /root/.vnc does not exist, creating.
Password: Warning: password truncated to the length of 8.
Verify: Passwords do not match. Please try again.
```
Password: Password too short
The command '/bin/sh -c cat password.txt password.txt | vncpasswd && rm password.txt' returned a non-zero code: 1`
Tried setting up a longer password but didn't work.

Reproduce the local Docker image build and inspect the Dockerfile commands shown for copying password.txt and piping it to vncpasswd. Confirm the cause of the password mismatch or length failure, then verify that the image builds successfully with the documented password setup.

Written by the indexing model from the issue text.