Having trouble with scraping the links images in slider

I am just starting out with webscraper and get a little stuck.

On this link:
http://simmerrealestate.com/property/unieke-droomvilla-aan-zee-met-een-goed-verhuur-rendement/

i am having trouble to scrape the link from the images in the slider.
I have read several threads on this forum, as to use the element attribute, however cant get my head around.

Also: Do i need to create a new selector for each image in the slider or can i do them in 1 selector

Sitemap:
{id:"{"_id":"simmerrealestate_goed","startUrl":["http://simmerrealestate.com/property/unieke-droomvilla-aan-zee-met-een-goed-verhuur-rendement/","http://simmerrealestate.com/property/schitterende-villa-met-zeezicht-te-vista-royal/","http://simmerrealestate.com/property/ruime-verdiepingwoning-met-zwembad-in-de-wijk-matancia/","http://simmerrealestate.com/property/appartementen-te-koop-en-te-huur-op-kleinschalig-complex-met-zwembad/","http://simmerrealestate.com/property/luxe-en-modern-appartementencomplex-inclusief-inboedel-te-koop-op-curacao-in-de-rustige-en-zeer-centrale-wijk-klein-piscadera-julianadorp/","http://simmerrealestate.com/property/ruime-woning-met-zwembad-appartement-en-studio-te-villapark-girouette/"],"selectors":[{"id":"adres","type":"SelectorText","parentSelectors":["_root"],"selector":"address","multiple":false,"regex":"","delay":0},{"id":"te_koop/te_huur","type":"SelectorText","parentSelectors":["_root"],"selector":"span.status-label","multiple":false,"regex":"","delay":0},{"id":"prijs","type":"SelectorText","parentSelectors":["_root"],"selector":".price span:nth-of-type(2)","multiple":false,"regex":"","delay":0},{"id":"custom_id","type":"SelectorText","parentSelectors":["_root"],"selector":"span[title='Property ID']","multiple":false,"regex":"","delay":0},{"id":"bedrooms","type":"SelectorText","parentSelectors":["_root"],"selector":".property-meta span:nth-of-type(2)","multiple":false,"regex":"","delay":0},{"id":"bathrooms","type":"SelectorText","parentSelectors":["_root"],"selector":".property-meta span:nth-of-type(3)","multiple":false,"regex":"","delay":0},{"id":"oppvervlakte","type":"SelectorText","parentSelectors":["_root"],"selector":"span[title='Lot Size']","multiple":false,"regex":"","delay":0},{"id":"description","type":"SelectorText","parentSelectors":["_root"],"selector":"div.content","multiple":false,"regex":"","delay":0},{"id":"image","type":"SelectorElementAttribute","parentSelectors":["_root"],"selector":"a#swipebox-close","multiple":false,"extractAttribute":"href","delay":0}]}"}

This site stores all its image URLs in the source code, so you do not even have to click. So something like:

Type: Image
Selector: div.slider-main-wrapper ul.slides > li > a img
Multiple: Yes (checked)

This would generate a lot of data though, e.g. if there are 15 images, you would get 15 lines of data.

thank you. Could you elaborate a bit on how did you come up with this solution.

As for this link i am stuck as well. And didnt have any succes using the image type