After discussion with some people (especially Tannin) on the en.wikipedia, I propose a few changes (more like additions) to the thumbnail function.
Here's the "main proposal":
[[image:bla.jpg|thumb|some text]] generates a normal thumbnail [[image:bla.jpg|thumb=bla_small.jpg|some text]] uses "bla_small.jpg" as the thumbnail
This associates the manually created thumbnail with the larger image in a machine-readable fashion. It should only be used if the manual thumbnail is of significant better quality than the automatic one, or if the manual thumbnail shows an alternate view (e.g., only a part) of the larger image.
Additionally, the automatic thumbnail generation should be improved: * Add a little sharpening, at least to photos (.jpg/.jpeg). * Apparently, automatically generated thumbnails look nicer when they are recaled by an exact even number. For example, for a 640x480 image, a thumbnail of 200px is requested, generate one with a width of 213px instead, as this is a factor of 33.3%, or 1/3. I propose to use a variation of up to 10% from the requested width.
If there is no special reason *not* to do this, implementation can start soon. At least the "main proposal" should be easy enough to code.
Magnus