Option to add custom emojis

Option to add custom emojis

It is nice to have the option of adding emojis to text. But the list of available emojis is short and usually exactly the kind of icon you are looking for is missing!
I'd like to have product or service icons like facebook, dropbox, iCloud, twitter, OneNote, ...

It should be possible to add custom emjois, as e.g. gif or ico files; in ideally 3 typical sizes: small mid, large