flash point
the lowest temperature at which a volatile fuel produces enough vapour to form an explosive mixture when it comes in contact with a flame.
so the lower the flash point, i.e. the temperature, the more dangerous is the fuel...but also means that the fuel will combust more readily than others as it is more volatile.
ignition temperature
the minimum temperature at which a fuel/air mixture spontaneously ignites (without contact with a flame)
so the lower the ignition temperature, the more dangerous and volatile the fuel
similar but not the same.