Ciaran 
"[@Rainbow Clouds":](/1909927#comment_7728545
)
That information, and other information about the image requirements for the collaboration, are available [in the post that introduced the collaboration":](/forums/art/topics/2019-derpibooru-community-collab
)
"Images of a pony sitting or standing on all fours should be a minimum of 800px in height, head-to-hoof. 1200px is preferred"
Also, the background must be transparent. It you need help with your image, you can ask in the collaboration thread.
Senior Moderator
友情は魔法だ
That information, and other information about the image requirements for the collaboration, are available [in the post that introduced the collaboration
"Images of a pony sitting or standing on all fours should be a minimum of 800px in height, head-to-hoof. 1200px is preferred"
Also, the background must be transparent. It you need help with your image, you can ask in the collaboration thread.