Merge works a bit differently than what you’re asking for. With “Merge”, you are taking two individuals and combining them into one. This means that all the encounters are preserved as they were before the merge, but they now roll up to a single individual.
Combining encounters is actually something that has recently been cropping up more as a request (@PaulK I swear, I saw the feature request, I just have been scrambling and haven’t answered yet!) because people are leveraging more powerful tools like bulk import and there’s more machine learning making decisions, which occasionally means more clean up.
For now, what you described, deleting the encounters and adding those photos to the other encounter, is the only real option. Keep an eye on this post (Need manual assignment/linkage of tail (part) to body annotations) for news about the ability to make these adjustments in a more intuitive and deliberate way.
Tanya