Back to the subject of adding your own emojis and to play devil's advocate for the idea, I see no harm in allowing you to save your own custom set of links to emojis as long as they remain outside links and do not break any rules.
This would be an option in the User CP, and it would allow you to save up to ten different image links. These then would become available under "Get More" on the Post Screen and would only be available to the user who set them. These would, ideally, be scaled down automatically to match the current emoji size. You may have to set file size and image dimension limits.
I don't have the ability to design such features, however, so I don't know how feasible it is.
This would be an option in the User CP, and it would allow you to save up to ten different image links. These then would become available under "Get More" on the Post Screen and would only be available to the user who set them. These would, ideally, be scaled down automatically to match the current emoji size. You may have to set file size and image dimension limits.
I don't have the ability to design such features, however, so I don't know how feasible it is.