What transformation has changed the parent function f(x) = log4x to its new appearance shown in the graph below?

The shape of this graph is clearly a reflection of normal log function by x axis. So the first step is to reflect log4x by x axis. When x=4, log4x=1, but in this case, the function is equal to 2 (after reflection). So the graph must have been stretched by a factor of 2 along y axis, which is the second step.