you did i’m sure. so the answer to your question is a challenge because there are a few factors involved. what type of wood? pressure treated, white wood, or some sort of hardwood? if it’s pressure treated, then 1×4 for pickets is probably fine, although i’m not sure it would look good mixing 1×4 and 2×4 pickets, but it might not be very obvious. no matter what kind of wood it is, thinner wood will generally not last as long as thicker wood so i can’t really say it’s “as good” as 2×4 lumber. but i would say that 1×4 is the standard for picket fence pickets. if possible i 