docs: Clarify bumping the runtime images step

This commit clarifies the docs to mention the case where users are
simply interested in bumping the runtime images to update to the latest
package, and don't necessarily have "a branch with changes".

Signed-off-by: Chris Tarazi <chris@isovalent.com>

Documentation/contributing/development/images.rst

@@ -1,5 +1,5 @@
 .. only:: not (epub or latex or html)
-  
+
     WARNING: You are looking at unreleased Cilium documentation.
     Please use the official rendered version released here:
     https://docs.cilium.io
@@ -150,9 +150,11 @@ update:
 .. image:: ../../images/cilium-quayio-tag-3.png
     :align: center
 
-6. A new pop-up will appear and you can select the branch that contains your
+6. A new pop-up will appear to select your desired branch.
+7. If you're interested in simply bumping the image to have the latest
+   packages, then select the release branch (i.e. v1.7, v1.8). If you already
+   have a branch that contains changes, select the branch that contains the new
    changes.
-7. Select the branch that contains the new changes.
 
 .. image:: ../../images/cilium-quayio-tag-4.png
     :align: center