> Does anybody know how they have managed to achieve applying a filter > to an image larger then 2880 px.
If they are applying it to images larger than 2880px, then they *have* to be breaking it into tiles. For filters that have a larger convolution filter than the pixels they modify (like a blur filter), they likely overlap the tiles to whatever degree is necessary, then stitch them back together. I would imagine the bulk of the "hard work" that Picnik does is in managing these tiles and supporting images of digicam sizes. Troy.
