I just spent six hours banging my head against this issue and so I thought I'd post here to save others from the same frustration.
I'm building a site on a live server "in private" using FoxyShop and the Maintenance Mode plugin. I found that when Maintenance Mode was active, I couldn't upload product images through FoxyShop's product image tool. I found that in order to make it work, I needed to set (in Maintenance Mode's settings) the Uploadify script directory to be available while Maintenance Mode is on.
Uploadify is the script FoxyShop uses to produce the Flash product image uploader.
To find the Uploadify script directory:
- view the product editor's page source code
- copy the directory information
/upload-deecXXXXXXXX/into Maintenance Mode's "Paths to be still accessable" box.
- Note: The XXXXXXX will be actual characters.
- click "Save Changes"
script : 'http://www.yourdomain.com/upload-deecXXXXXXX/',