Add Specifying a custom image tag exercise.

episodes/image_management.md

@@ -17,7 +17,35 @@ After completing this episode, learners will be able to...
 - explain value of reproducibility provided by images
 - describe how software images are integrated with their hub environment
 - evaluate whether an existing image meets users' software needs
-- manage images available on their hub instance
+- pull an image container to make it available on their hub instance
 
 ::::::::::::::::::::::::::::::::::::::::::::::::
 
+:::::::::::::::::::: challenge
+
+### Specifying a custom image tag.
+
+Which of the following would you paste into the _Custom Image_ field to add the latest version of the `handbook-authoring-image` image to your hub?
+
+1. quay.io/2i2c/handbook-authoring-image:bbe4225a7940
+1. quay.io/2i2c/handbook-authoring-image
+1. docker pull quay.io/2i2c/handbook-authoring-image:ad18f6ea575d
+1. quay.io/2i2c/handbook-authoring-image:ad18f6ea575d
+
+
+::::::::::: solution
+
+4. quay.io/2i2c/handbook-authoring-image:ad18f6ea575d
+
+Notes on the other answers:
+
+1. This is using an older version tag and not the latest version.
+2. This is missing the version tag.
+3. Need to remove the 'docker pull' part.
+
+
+::::::::::::::::::::
+
+::::::::::::::::::::::::::::::
+
+