That is definately a big 26 next to a 22. The brown one is definately a 22 because look at where the lid handle is in relation to the lid vent. The vent is at the end of the handle. If it were an 18, the vent would be alongside the handle, not at the end of it.
The big one is definately a 26. Look at the built in factory thermometer on the lid only available on a 26. Look at the rubber tip on the end of the lid vent damper. Only available on a 26. Also, look at the knobby tire tread on the big one, only available on a 26.