GUI ImageSlider

can anyone help to implement GUIImageSlider ?

You might want to use simple planes instead of using the GUI for it. You should put an empty gameobject in front of the camera, then put some planes into it as children, facing at the camera. Then put the images as textures on the planes and make two GUI.Buttons like next and previous and write the corresponding script, to move the empty gameobject smoothly on the X axis (provided you use that as the images’ axis)