[OAM-talk] a dramatically simplified technical proposal

[Keith Jenkins]

>> Image tiles should be 256x256 pixels in 8- or 24-bit compressed PNG format
>
> I understand the desire for transparency, but I'm not entirely sure
> how we see it being used.

I agree that JPEG makes more sense for imagery.  My guess is that the
transparency info would be needed in order to merge tiles from
different layers into a global layer.  For example, one layer might
only cover half the tile.  Maybe there is another way to address this
problem without depending on PNG transparency... perhaps by using the
bounding box metadata?

Keith