Hi there! It's not that hard to make but it takes some time. Firstly I draw runner trough 10 different positions so it looks like (s)he is running. Then apply every position, one by one, onto original image... At the end, if I remember well, it was about 35 images. Finally, I made the gif of it. I used GIMP to make it. I am not any advanced user so I am sure anyone could do it.
Thank for stopping by and asking, @blessed-girl!