Failing to create thumbnail, medium and large images When using a new installation of Drupal 7.10, I have set the directory for public uploads to sites/uploads. 

When I then add an image to a content instance, I get the original uploaded to sites/example.org/files/imagename.png as expected. However, the other images (thumbnail, medium and large) do not get created at sites/example.org/styles/*. 

The directory is readable and writeable by the PHP5-FPM user, and so there should be no issue permissions wise. 

Why does this happen? How can I fix it?
Right, the answer is in fact a little more subtle than I realised. Turns out that D7's imagecache replacement needs some attention in your nginx vhost. Without the 404s being sent to Drupal for the missing files, the images are not created - something I didn't realise initially, as I'd assumed they were created on upload.

location @rewrite {
    rewrite ^/(.*)$ /index.php?q=$1;
}

location ~ ^/sites/.*/files/styles/ {
    try_files $uri @rewrite;
}


It needs to be added to your server definition, and you should be ready to roll. Clearly, the path may need altering for your setup, but for mine it was.