How to change the images of the collaborative Workbench

Hi team --
we want to change the images of the collaborative Workbench.

Please provide your action plan how we can apply the above changes in test instance.

I need the following details before apply the changes in SCPT

1) take the backup of the current images in collabrative work benck..

2) Check if we can revert back to changes if there is any problem after applied..

3) Does it  impact of this change in collbrative workbench

4) Can we do it this for user/responsibility level.

Please let me know how I can access to Demantra_root/Collaborator/portal/images server in DEV/TEST environment.