As for animating textures, there is no possible way to control the animation and they can usually only have 10 frames (ie, +0~texturename, +1~texturename, +2~texturename, ect)
They are not customizable and you cannot control them in any way. You can pretend to slow them down by using the same image in duplicate frames so that it uses the same image for longer than one frame, but then you use up twice as many frames doing this.