How to manage ITHMB files on your PC and iOS devices

Now that the previous articles have covered general information about ithmb files (name, location and size) you still may be wondering: what is the iTHMB format?

To answer your questions, we can look more closely at answering some technical questions.  Let’s begin with where we left off – synching photos and the difference with files stored on your computer and the ones on your device.

What are the differences between files stored on the device and the computer?

When you perform a sync using your iOS device and your computer, iTunes will create a cache folder on your computer that includes the database index file (for storing metadata), and subfolders for storing iTHMB files.  The folders (which range from F00 to F50), store the files with the following filename format: T###.ithmb. 

There is a difference between the files stored on the iOS device (iPod, iPhone, iPad), and those stored on your computer’s hard drive despite what may appear to be similarities.  If you are using a previous iOS version, the file name would be F####_#.ithmb file and for a newer version: AxB.ithmb.

* Note: these are the files that are created when synching the iOS device (old or previous version).

An iTHMB file on your device will contain a number of smaller copies of the images in the same image dimension.  The file on your computer (T###.ithmb), contains copies of a single file in a number of various image dimensions.  The result of this is that you can sync your images, and for each image a new iTHMB file can be generated on your computer.  One result of this is that the cache folder that is generated will be considerably larger in size than the total size of your original images.  If you have space concerns on your computer, this can be a factor.

What are the effects of deleting the folder from my computer?

If you have the original files on your device, deleting the cache folder that was created on your computer will have no serious consequences.  Keep in mind that these are copies of the original images.  In fact, if you are experiencing sync errors and you have the originals intact, it is good practices to delete the iPod Photo Cache folder altogether.  These items are recreated when you perform the next sync.

What are the iTHMB file formats?

The image format of the files contained within the iTHMB files are not popular image formats such as JPEG, BMP, or PNG.  The iTHMB file is an interlaced format (one intended for TV output).  The color encoding is not standard RGB.  An iTHMB converter or iTHMB viewer is required to convert and view any iTHMB file.  If you want to view the images on your computer you will need a converter application.