RE:
Upon further investigation, it appears as though the problem is not the file location but the files themselves. I used httputils to download the image files from our web server. The download goes successfully, and all of the files appear in the proper folder on the device. However, there appears to be a problem with the files. If I try to view one of them using Gallery, nothing happens. Also, the icon that appears by the file name in file manager, which is actually a mini-image of the file, is not the image at all -- some generic-looking icon thing. I am going to have to troubleshoot what is happening to the files during the download process. Not looking forward to that!