The way in which the phrase "tiny dots" suggests the islands as it is used in this sentence is that The islands are small and scattered in the water
This refers to the hints and cues which are given about a given scenario to give a better understanding of the setting with the use of word clues.
Hence, we can see that from the given passage, there is the narration of the islands and how they looked like tiny dots in the water and this is a context clue which is used to show that the islands are small and scattered in the water.
Read more about context clues here:
https://brainly.com/question/24750804