How does Apple TV sort photos from PC home sharing?

Unfortunately, whilst your PC may list your photos alphabetically in your folders, it does not keep a database or directory of that order (unlike iPhoto on a mac). Consequently Apple TV cannot work with it in that way, and will merely read the photos from your PCs hard drive in the order in which they were written to it.

As I mentioned earlier, it plays them in the order in which they were written to the drive on the PC. Unfortunately that order is completely random and you have no control over it.

I did some additional testing using my Apple TV (1st generation) and my Windows 7 computer, and this is what I found.

(This likely applies to iPad/iPod/iPhone too).

• Apple TV displays photos in order of their "Date Created" file attribute.
• If the "Date Created" file attribute of all photos in an album is identical, then Apple TV displays the photos in alphabetical order.

This I what I do to make sure that Apple TV displays photos in the order I want them to be in:

• First, I arrange photos in the order I want them to be in. For this, I use Google Picasa, but one could also use FastStone Image Viewer, or any similar tool.
• Then, I bulk rename all the photos, so that their file names are in alphabetical order. I do this from within Picasa, but there are many other freeware file rename tools one could use for this.
• Next, I bulk change the "Date Created" file attribute of the photo files, so that they all have an identical one. For this, I use BatchTouch, freeware available for Windows and Mac.
• Finally, I open iTunes, and sync the photos to my Apple TV.

Note: if they photos were already synced to your Apple TV before you perform the steps above, you may need to this beforehand:

• Open iTunes on your PC, and make sure that the correct photo folder is selected for syncing to your device.
• Using Windows Explorer, navigate to this folder.
• Within it, locate a subfolder called “iPod Photo Cache” ("iPad Photo Cache for iPad syncing) and delete it.

In addition to the steps above, I forget to mention that also the "Date Taken" in the EXIF-metadata needs to be set to an identical value for all photos. To do this, I use FastStone Image Viewer. Using this tool, I just delete all EXIF-data of the photos I want to sync to my Apple TV. Select the photos you want to work on, go into the Tools-menu and select Remove JPEG metadata.

Note: this action will also delete all other info which is stored along with the photo, such as camera make, etc. If it is important to you to keep such metadata intact, use another tool which is capable of modifying EXIF dates.

Symptom

Playing slideshow the sort feature does not work. This issue happened with albums that had 100+ 500+ 1000+ 5000+ pictures on each album. When playing slideshow, you would only see 10 photos or 20 at the most and go back to the first photo going on a loop. This issue happened on Apple TV 3rd Generation and new Apple TV 4th Generation.

Resolution

Create a new empty album (you can give it the same name), select all photos and move them to the new Album, if you are prompted to confirm “Are you sure you want to apply this action to {number} photos?”, cancel it and move the photos by groups, if you have 500 photos, select 100, then another 100 and so forth. Make sure you don’t move them all at the same time. If you move them all at the same time, the issue will persist. This solution only works on the Apple TV 3rd Generation!!

Steps Taken - The steps taken to resolved this issue were very very extensive...

• We had Apple TVs 1st generation that using the Slideshow feature the sort order worked perfectly, but after they died we had to buy new Apple TVs - we purchased Apple TV 3rd Generation. Apple TV 4th Generation was not released yet. All Mac Mini Server were already using the new Photo app.
• Playing slideshows we noticed the photos were not in order
• We erased Apple TV to isolate any possible issue with Apple TV. Issue persisted.
• We purchased a new Apple TV 3rd. Issues persisted.
• Contacted Apple Support to find a solutions, we followed their recommendations, but issues persisted.
• I went to an Apple Store with Genius reservation... issues persisted.
• Followed recommendation from Apple Support Site - issues persisted.
• We updated two Mac Mini to 10.11 bringing updates and fixing bugs on Photo app - issue persisted
• We decided to use iCloud Photo Library to keep all photos synced. Issue persisted
• At the time we got the other two Mac Mini we restored everything from Time Machine backup (Mac Mini are for two other locations)
• To isolate any issues/corrupted backup we did a clean installed on one of the Mac Mini, but we only copy the Photos Library (we wanted to speed up the process and prevent using all Internet bandwidth). Issue persisted
• We disabled iCloud Photo Library on all computers, deleted the Photo Library on one Mac Mini and downloaded all photos using iCloud Photo Library. Issue persisted.
• At this point issues are not related to any of the computers, Time Machine backup, corrupted Photo Library, iCloud Photo Library
• We setup static IP address on the Apple TV to isolate any network issues. Issues persisted.
• We turned off all Firewall settings on the network temporarily. Issues persisted.
• New Apple TV 4th Generation came out... we got it. Issues persisted.
• It just happened that we created a new album and added photos from a recent trip. We added it to Share it with the Apple TV, we played the slideshow and noticed that Photos were in order.
• Turned out that all the albums already in our Photo library were albums migrated from iPhoto. Something happened in that process that created a conflict or corrupted current albums. We created new empty albums and transferred all photos from current albums to the new empty albums. Issue resolved. Read resolution for more details.

... i forgot to include that throughout the troubleshooting process I also attempted to repair the Photo Library, but issues persisted.