Final answer:
To enable SSH on a Cisco device, the IOS image must have cryptographic features, typically labeled as a K9 image. This indicates the IOS has enhanced security feature sets, including SSH support.
Step-by-step explanation:
To enable SSH on a Cisco device, the IOS image that should be installed is the one that includes the cryptographic features, which is typically labeled as a K9 image. The K9 in the IOS image filename stands for the enhanced security feature set which includes Secure Shell (SSH) support among other features. For example, an image with a filename like c2600-adventerprisek9-mz.124-15.T14.bin indicates it is an Advanced Enterprise Services image with the cryptographic (K9) features necessary for SSH.