The principal Buddha image in the old ordination hall of Wat Sala Daeng is named Luang Pho Muang Haeng (commonly known as Luang Pho Yai), a sacred Buddha statue in the subduing Mara posture with a lap width of 59 inches and a height of 74.5 inches, crafted in 1921 to serve as the spiritual centerpiece of the temple's original hall. The image is majestically enshrined amidst ancient murals depicting the life of the Buddha during the Maravijaya episode and the Vessantara Jataka, which profoundly enhance the solemnity and faith for devotees who come to pay their respects. The origin of the name Luang Pho Muang Haeng is linked to the temple's former name, "Wat Kaeng Muang," which was once symbolized by a large mango tree before it was eroded by water, making this Buddha image a living historical representative of this riverside community to this day.