In Aseprite a document/file/sprite has the following properties:
- It has a size in pixels (width and height).
- It has a color mode, which tell you how many colors the image can handle. All images in the sprite are in one specific mode, you cannot mix RGB images with Indexed images in the same sprite.
- It contains a set of layers. You can see them in the Timeline. The most important concept here is that there are two kind of layers: the background layer for opaque sprites, and transparent layers. A sprite can contain only one background layer, but several transparent layers.
- It contains animation frames. Each frame has a duration, i.e. how many milliseconds the frame must be on screen when the animation is being played.
- Each layer/frame intersection is called cel, and contains the image where you finally can paint.