Raw Image support is under discussion to be removed. Please voice your opinion here if you believe Kavita should keep it.
Raw Images (Manga/Comic) library types are supported as loose leaf images within a folder. It is advisable to put a second folder named Volume 1 (and chapters if needed) so that the files are grouped as one volume, otherwise they will all be separate specials.
└── Manga 2
└── Vol1
└── Ch1 - Ch3
├── Image 1.jpg
├── Image 2.jpg
└── Image 3.jpg