As well as using the highest available quality resize filter, subscriber's images also receive a small amount of image post-processing, in order to bring out some extra detail that some phone cameras, and the resizing process, loses.
Below is an examples of the two levels of image processing (camera: Sony Ericsson S700i, model: Elvis)
Quality setting: normal
Quality setting: very high
The Technical Bit
Images are processed using Imagemagick. Imagemagick resizes, gently filters noise from the image, boosts saturation by a tiny percentage to compensate for colour information being lost in the resize operation, then creates a thumbnail.