Using a bathroom in Mexico can be quite an adventure. One never knows what to expect. Some of the “irregularities” that you might encounter are: no seat – no flushing capability except for a bucket of water or no toilet tissue.
All or any of the above can occur The banos are usually clean but not always and that can lead to another whole adventure if the need is an urgent one.
The sink is usually outside and probably has the hot water handle removed. Soap for washing your hands can vary but is normally laundry soap in a margarine or similar container or liquid soap. Sometimes the tissue is outside. This helps to hone your observation skills in finding it. Speaking of tissue, it is never flushed. You put it in a wastebasket. Similar to being on a boat.
The picture of the toilet outside is, of course, a joke. Someone thought it was funny as it was on an island which is a bird sanctuary and also has a great beach for snorkeling. The island did not have any bathrooms and visitors had to, well, off to the woods you would have to go. This seemed strange given that it was a bird sanctuary.