In my last post I explained how to use the Photoshop Elements’ (PSE) Copy/Move to Removable Disk feature to move part of your collection to lower cost disk while still retaining visibility within your catalogue.  To make the best use of this feature there are a few caveats, and workarounds for them, you need to keep in mind:

1. No Photo Review/Compare of Offline Images: Despite allowing you to choose offline proxy file sizes as large as 1280 x 960 pixels, the Photo Compare/Review features will not display offline images unless the media is currently mounted.  While I understand the proxy file’s quality would not compare to that of an online file, why couldn’t they just display the "offline file" icon to explain the lower quality image (like they do in the main browser UI)? 
   Workaround: Photo Review can be emulated in the PSE browser by zooming the offline file to maximum size.  Photo Compare can be emulated in a similar way by adding tags/collections to the images, selecting them, then zooming so only two photos appear in the PSE browser.
2. Directory Structure Flattened During Move: All of my photos are stored in a YYYY-MM-MMM\category\yyyy_mm_dd_desc directory structure on my HDD.  When moving photos offline I’d like to automatically retain this relative directory structure but there is currently no way to do so without manually calling the Move Offline function once per destination directory.
   Workaround: Run Move Offline once per destination directory.  e.g. I move photos offline a month at a time.
3. No Way to Identify if Media Online: The Details Metadata query provides no way to search for media based upon whether they are offline or not.  It also provides no way to search by the volume the file is currently stored upon.  Offline photos aren’t automatically assigned tags or collections so this can’t be used to identify the files either.
   Workaround: Assign a tag to photos as you move them offline, and later use this tag to find or exclude the photos.
4. No Way to Move Images Back Online: Hard drives are becoming larger and cheaper all the time, so over time photos that had to be moved offline for space reasons may be able to be moved back online after hardware upgrades.  PSE provides no obvious way to achieve this.
   Workaround: Select files in the PSE browser and use the File\Move option to move files to an online directory.  Alternately delete files from the catalogue and re-import, but if using this approach you should File\Write Keyword Tags and Properties Info to File to retain captions and tags (collection information will be lost).
5. Cannot Bulk Relocate Images on Removable Media/Network Drives:  PSE does not provide any easy way to move the files once they have been moved offline.  This is particularly problematic when having to relocate images as media fails,  or larger media becomes available. e.g. a USB hard drive is lost or fails, or refresh optical media by moving DVD content to larger Bluray disks.  This issue is exacerbated by PSEs insistence on storing network drives as the underlying UNC paths, and identifying optical media by their serial number rather than drive letter, so you can’t just copy the files manually and map them to the same drive letter.
   Workaround: Use the "Move online" workaround, then move the images offline again.

As long as you adjust your digital photography workflow to take these caveats into account, the Move Offline feature remains an extremely useful way to make use of your precious disk space.