I am having a very strange problem. I am migrating old single WP blogs into a newly created WP Network. After creating the new blog on Network and importing the posts,including attachments, images do not appear in posts, nor as thumbnails. I made sure the images were imported from the old blog, they are in the new blog's folder in the server. But browsing to the URL of the image gives a missing image placeholder.
However, if the image is accessed through the main site's (Network's) URL, it appears just fine.
Example: Viewing this message shows nothing: http://2armedia.al-rasid.com/files/2012/09/rabieiee-150x131.jpg
Viewing this shows the image fine: http://al-rasid.com/wp-content/blogs.dir/8/files/2012/09/rabieiee-150x131.jpg
Noting that "2armedia.al-rasid.com" is subsite 8, and that the 1st url is the default url of the image after being imported, and the url given to all images by the network.
I tried everything, including changing the "Upload Path" and "Upload Url Path" settings of the sub blog to "al-rasid.com/wp-content/blogs.dir/8/files" (including the http) , but that didn't help.
I deleted the network and re-created it because this issue drove me crazy, and that didn't resolve it (what are the default values for these two fields anyway?).