Possible to add own emoji set to chat + shoutbox ?

Is it possible to add an own emoji set to chat and / or shoutbox?

And if so, how could this be achieved? 

There are smilesets for Flash Chat and Messenger:

https://www.boonex.com/m/Smilesets_for_your_Chat_and_Messenger_2010_01_16

I am puting together an own collection. I need the information how to insert them technically in chat and shoutbox. Besides i wonder why in shoutbox i see colored versions in the chatbar but as soon as the smilys are sent i only see the different black version of it. So that is also why i am asking if and how this can be changed to an own set of emojies.

It's because when selecting emoji you actually see an image, when it's inserted - it's inserted as unicode image, emoji images looking different on different systems.

Would it be possible to circumvent this system and add own images (emojies) instead?

It's not possibly to easily replace emoji in Shoutbox & Text Messenger. 

However it's possible to add own smilesets in Chat+ and TinyMCE

Have you considered to use those in dolphin?

https://www.emojione.com

Not yet, but maybe in future we'll use another lib, including this one.