I remember a very specific rastering effect with loading images, probably around 1994-1996? The image would load every nth line and then iteratively nth line + i until i==n. Compared to what I would see later (just loading in every line from top to bottom), you could get a sense of the whole image sooner, just in an increasing fraction of the vertical resolution. I can't recall which image type this was or whether it was Mosaic or Navigator, but the effect was very distinct; at the time I assumed it was the way the image data was streamed in, but now I'm wondering whether it was just the way the image codec built the viewable bitmap.