Final answer:
Imagery suggesting that Tom's discovery won't be pleasant would be characterized by negative and foreboding descriptions in the text. The presence of descriptive language that sets a gloomy mood indicates an unpleasant revelation.
Step-by-step explanation:
The imagery in lines 189-192 that suggests Tom's discovery won't be a pleasant one can be identified by the tone and language used in that section of text. If the descriptions are negative and foreboding, this would indicate that the discovery will likely be unsettling or unwelcome. This is opposed to positive and colorful descriptions or detailed and uplifting language, which would suggest a more pleasant revelation.
When analyzing such a passage, look for descriptive language and the mood set by the words chosen by the author. The use of precise color names, similes, and metaphors can help to visualize and understand the scene and its implications. Phrases or words that convey a sense of danger, sadness, or unease contribute to a negative and foreboding atmosphere, implying the discovery will not be enjoyable.