Question:  how to split a value that is defined in Evaluate variables ?        

Answer:-

    Use  SPEL which supports JAVA expression which help's to split

          Existed variable in the evaluate variable stage

           image : "index.docker.io/dockerrepo/demoimage:2021-12-01-201526"

                                 Here is the image with the tag and need to extract the tag with ":"?

           Add a new variable in the evaluate variable stage as below

          newkey: ${image.split(':')[1]}

RESULT:-  Tag is extracted

                     2021-12-01-201526