IFF (Interchangeable File Format) is a container format that can contain different types of data. ILBM (InterLeaved BitMap) was the image encoding inside the IF

IFF (Interchangeable File Format) is a container format that can contain different types of data. ILBM (InterLeaved BitMap) was the image encoding inside the IFF. The Amiga had bitplane-based graphics. The "interleaved" part was that an image was stored by line first, bitplanes second instead of one whole bitplane after the other. Games often used the "interleaved" graphics layout in memory because it allowed blitting a sprite with a single Blitter operation. (... and EA who made DPaint was a games studio first)