Use Day Recap
Choose photos from a day and turn them into a journal entry.

Open a recap
When you have already kept an earlier day and there is no entry for today yet, Day Recap appears in your timeline. Open it and review the available images one at a time.
Choose
Keep the photos that belong to the day. Skipped images are not deleted and are not suggested again in later recaps for that day.
Finish
Add a thought if you want, then save the entry. You can still edit it later.