Hello,
do thumbnails really have to be this large? http://en.wikipedia.org/upload/thumb/a/a1/350px-Nyc-un-building.jpg
The main purpose of thumbnails is, of course, to prevent full-size images from cluttering an article. My perception is that another purpose is to spare visitors with slow connections from having to download large images if they're really only interested in the text of an article.
It seems that a lot of people have begun to make thumbnails excessively large. For visitors with low resolutions, 350px is a *lot* -- especially if their browser window isn't full-screen. 350 more than half of 640 -- add to that the sidebar, and there's not much left for the actual text. Purpose #1 is therefore not fulfilled.
Also, it makes the files pretty large. 14KB doesn't sound large to DSL people, but on ISDN it would take 2 seconds to download on maximum speed. Add to that the fact that Wikipedia isn't always at maximum speed, and that many people don't even have ISDN! Purpose #2 is therefore not fulfilled.
Arguments I have often heard regarding this are that you can't see a lot of detail on thumbnails that are too small. I fail to see how that has any relevance to *thumbnails* -- thumbnails are supposed to give a quick glance of an image. People who want the details are supposed to click on the thumbnail to see the full-size picture with all its details.
Please consider making the thumbnails smaller.
Thanks, Timwi