1. WHAT‘s 8-bit /16-bit/32-bit images
Remember, 8 bit, 16 bit, and 32 bit images are NUMBER OF BITS PER CHANNEL! There are basically 3 channels in an RGB image, so that's like 24 bit, 48 bit, 96 bit respectively.
That is because one term describes the number of bits per channel, while the other describes the number of bits per pixel.
32 bit often refers to 24 bit, though 32 bit is actually 8 bits per channel, with an extra "alpha" channel (for transparency).
Reference: https://www.instructables.com/RAW-8-bit-16-bit-and-32-bit-explained/