Here’s a quick question I got today that may be of use to some: “Can you control the upload space quota on a blog-by-blog basis in WPMu?” As of version 1.3.x administrators now have this useful option.
The overall setting for upload space quota is set in the Site Admin tab under the Options subtab, as featured below. This will be the default upload quota for all the blogs on the system.
More granularly, with WPMu 1.3.x system administrators can override the upload space quota on a blog-by-blog basis by going into the Site Admin tab and clicking on the blogs subtab. From there find the blog you want to change the default settings for and clik on the edit link for that blog, as shown below.
From there you will be taken to a series of details about this particular blog, in the right column at the bottom you will see the Misc Blog Actions settings where you can put in the value (in MBs) of the new upload space quota for just this blog. Pretty simple, just the way we like it.