A very interesting discussion here! My two cents to add to the dollar! :) Usually I resize my stuff downto 200 pix as max size, depending landscape or portrait format. After a little sharpening I post the thumbnail, but now and then it's more than 15 kb, so I need to leave it a bit more blurry, or blur a part of it. Automatic resize would be a great thing, but there are postings with pictures containing lots of details and a resized version of it as thumb is just a kaleidscope of colors, nothing more. It would do no justice to the original picture to post a thumbnail like that, so in that case I crop the original picture and resize it to thumbnail format.

• As I read the earlier comments I see several interest-roles:
• the interest of the artist (easy uploading, great artistic freedom)
• the interest of the viewers (easy browsing)
• the interest of the administrators (little load on performance and fast browsing).

Finding a way to optimalise the system, to add automical thumbs if not uploaded, would be great. Question is, should it be an obligatory function, or would it be better to leave artistic freedom to the one posting one's artwork?