Use the chart. Pics can be deceiving. In the first two pics the snake looks fairly small. Ready for rat pups or maybe weans. The last pics it looks much larger. Ideally you go with the chart or by body width, at least until they are mature. Males never need anything bigger than a small rat and females mediums once the hit adulthood. If i went by the body width rule for my breeding females they would be eating cat sized stuff.