Eric Scott (Beacon High School in Manhattan, New York)
shared two Geogebra files he created on teaching transformations in Algebra 2.
Students see the effects of a, b, h, and k on a function i.e. g(x) = a*f[b(x-h)]+k where f(x) is the parent function. Eric reported that students enjoyed doing transformations with Spongebob.
Eric used this video tutorial to import an image (Spongebob) into the program:
Technology in Mathematics Education 