I'd imagine this was depicting Eila. Suomus badge, Eila's colours for hair, eyes, and on the bag and her clothing too. Plus the diamonds are a good pointer, since she's the Diamond Ace.
Looks as good with the short hair as she does with long hair.
picnic said: The lineart appears in this twitter post but the accompanying text/comments aren't very telling.
As it turns out, the text is the title of the picture and tells who the character is. イッルくん is for "Illu"; A Japanese pet name for Eila based upon the first two letters of her middle name "Ilmatar".
