Traditional Japanese haiga involved brush art work coupled with a haiku poem done in brush calligraphy. And traditional haiga is still practiced in the West and East.
Digital art-haiku is one form of modern haiga. Other forms include photo-haiku [haiku attached to a photographic image] and all modern types of art coupled with haiku.
Just as the haiku form often contains a juxtaposition between two of its lines and a third line, so does or can modern haiga contain a juxtaposition between the haiku itself and the digital art work.In short, the art work does not necessarily directly represent the images presented in the haiku.
If you would like to see examples of other forms of modern and traditional haiga, simply search the internet with the following key terms: haiga, japanese, haiku.
Journals that carry contemporary and traditional haiga:
Examples of My Published Haiga