As you can see in this example, when you press < RIGHT > key, another images appear over the existing one.
Looking at the source code there is only one image .svg: http://www.inf.usi.ch/faculty/pautasso/talks/2012/soa-cloud-rest-tcc/img/interop-ws2.svg
How can i get this effect with another image?
According to this pull request on impress.js, you can simply add a class="substep" in the elements you want to appear after the < RIGHT > key instead of going to next slide.
You can extend your current impress.js just by adding the above patch.
