How to create drag like horizontal and stop at full image on first image

all the frame97 navigate to number/start/end use drag and animate like the picture
i test it, some time can drag like horizontal some thing one by one start to end, then i test from end to start it just can drag one by one
When the first image is high than 50%(width) to next image, lower than previous it


Not sure exactly what the question is?

link to see work, i change something