Because you are using a 32-bit machine, you use the standard 64-bit (x86_64) image. Go to the Batocera Download Page . Look for the x86 (32-bit) legacy section.
The "32GB" label refers to the pre-sized disk image: when written to a 32GB (or larger) drive, the system partitions it automatically, allocating ~6–8GB for the system and the remainder for user ROMs. Batocera 32gb Pc 32 Bits
: A 32GB drive (USB or internal SSD) is the "sweet spot" for 32-bit systems. It easily fits the Batocera OS plus thousands of 8-bit and 16-bit ROMs. Because you are using a 32-bit machine, you
Using a 32-bit system means working with older technology, which limits the consoles you can emulate. Version performance, outside of x86 vs x64? : r/batocera the system partitions it automatically