Live vs Life
I don’t think Mrs Ann Wee is going to be very thrilled to see this!
In the poster, she is referred to as a live member of the Singapore Children’s Society (opposite: dead member). In this noun phrase, the premodifier live is an adjective, e.g. live prawns, live wire, live connection.
Mrs Wee is in fact a life member, where the premodifier is the noun life and the expression means ‘member for life’.
When we have an adjective+head noun combination (here, live + member), it is usually possible to reverse the order and insert a linking verb: the member is (a)live. But when we have a noun+head noun combination (here, life + member), we can very often reverse the order and insert a preposition: member for life.