I pointed out (elsewhere) that thumbnail image quality is better when the rescale uses an
exact even number. (50%, 33.3%,
etc.). (Not under all circumstances, by the way. It depends of the resolution of the
source image. In general, the larger the
original the less it matters.)
Magnus proposed that the software generate a thumbnail *close* to the requested size (and
thus preserve as much image
quality as possible, at the cost of producing (e.g.) a 213px rather than a 200px thumb.
Erik said please don't do it as it would break many layouts.
Ahh! I hadn't thought of that!
No matter. Exact fraction resizes are really only required for a small proportion of
images - off the top of my head, maybe
10%. These can be hand-thumbnailed instead. As it happens, it is low to medium-resolution
originals that tend to have the
worst problems when autothumbnailed, and benefit most from human intervention, so the
reality is that we were probably
going to want to hand-thumbnail most of the images that could benefit from the (e.g.) 200
to 213px rescale anyway, so we
can simply leave the even-fraction rescale part out of the overhaul and not particularly
miss it.
Tannin (Tony Wilson)