[Update:7/5/2017] - Skype issue is now resolved. The carousel code that is working for Facebook Messenger will also work for Skype.
Sample JSON for Carousel on Skype:
{
"type": "catalogue",
"msgid": "cat_212",
"items": [{
"title": "White T Shirt",
"subtitle": "Soft cotton t-shirt \nXs, S, M, L \n$10",
"imgurl": "https://pixel.nymag.com/imgs/fashion/daily/2016/06/02/t-shirt/everlane.w710.h473.2x.jpg",
"options": [{
"type": "url",
"title": "View Details",
"url": "https://pixel.nymag.com/imgs/fashion/daily/2016/06/02/t-shirt/everlane.w710.h473.2x.jpg"
},
{
"type": "text",
"title": "Buy"
}
]
},
{
"title": "Grey T Shirt",
"subtitle": "Soft cotton t-shirt \nXs, S, M, L \n$12",
"imgurl": "https://cdn.shopify.com/s/files/1/0407/0829/products/Grey_t-shirt_front_1024x1024.jpg?v=1466588290",
"options": [{
"type": "url",
"title": "View Details",
"url": "https://cdn.shopify.com/s/files/1/0407/0829/products/Grey_t-shirt_front_1024x1024.jpg?v=1466588290"
},
{
"type": "text",
"title": "Buy"
}
]
}
]}
Result:

Images are not loading for the carousel on Skype because there have
been recent changes in Microsoft framework which are not yet
incorporated in Gupshup's bot platform. Although next week you should
be able to see those images load once we at Gupshup pushes the fix
into production. There will be no need of changing the code from your
end as the same code for carousel works across the supported
platforms.
I will update this answer once the fix is live into production.
PS: I work for Gupshup.