Artwork is from this Tumblr post: https://www.tumblr.com/crees-a/725369172861796352/uuuumm-that-was-super-fun-im-feeling-twelve
And I found it in Pinterest as well: https://www.pinterest.com/pin/1129910993998272790/
I may be asked to put this down from this website.

Rarity: https://derpibooru.org/images/3351951?q=uploader_id%3A690876

Applejack: https://derpibooru.org/images/3351954?q=uploader_id%3A690876

Rainbow Dash: https://derpibooru.org/images/3351955?q=uploader_id%3A690876

Fluttershy: https://derpibooru.org/images/3351967?q=uploader_id%3A690876

Princess Luna: https://derpibooru.org/images/3351968?q=uploader_id%3A690876

Pinkie Pie: https://derpibooru.org/images/3351975?q=uploader_id%3A690876

Spike:https://derpibooru.org/images/3351987

Scootaloo: https://derpibooru.org/images/3351988

Starlight Glimmer: https://derpibooru.org/images/3351989

Vinyl Scratch: https://derpibooru.org/images/3351990?q=uploader_id%3A690876