The picture that reveals the first sparks of the fire of revolt, according to me, is Picture 2 from NCERT Solutions - Chapter 3 : Glimpses of the Past.

Picture Description:
The picture depicts a group of Indian sepoys (soldiers) standing in a line, with their rifles and swords in hand. They are dressed in traditional Indian attire, wearing turbans and dhotis. The sepoys in the picture seem to be engaged in a serious discussion or planning.

Explanation:
The picture represents the initial stages of the Indian revolt against the British rule. Here's why I think this picture reveals the first sparks of the fire of revolt:

1. Symbolism of Indian Sepoys:
The presence of Indian sepoys in the picture is significant as they played a crucial role in the revolt. The sepoys were an essential part of the British Indian Army and were mainly recruited from various regions of India. Their involvement in the revolt signifies the growing discontent and the unity among the Indian soldiers against the British rule.

2. Traditional Attire:
The depiction of the sepoys in traditional Indian attire is a symbol of their cultural identity and pride. This suggests that the revolt was not only against the British political dominance but also a cultural assertion and a fight to preserve their heritage and traditions.

3. Serious Discussion and Planning:
The serious expressions and body language of the sepoys in the picture indicate that they are engaged in a discussion or planning something significant. This suggests that the picture captures a crucial moment where the sepoys are discussing their grievances, strategizing, and preparing for the revolt.

4. Unity and Solidarity:
The fact that the sepoys are standing together in a line portrays a sense of unity and solidarity among them. This unity was a crucial factor in the success of the revolt as it brought together people from different regions, castes, and religions to fight against a common enemy.

Conclusion:
In conclusion, Picture 2 from NCERT Solutions - Chapter 3 : Glimpses of the Past reveals the first sparks of the fire of revolt. The presence of Indian sepoys, their traditional attire, serious discussion, and the sense of unity portrayed in the picture all signify the initial stages of the revolt against the British rule. This picture captures the beginning of a significant historical event that would shape the course of India's struggle for independence.

Picture 7 'The sparks' reveals the first sparks of the fire of the revolt.