I have experienced this same problem with various file types in various created libraries.
I have found a solution that is both simple and effective and does not involve the need to change the Library view to one that is not appropriate for your content.
The basic instruction is to hide all subfolders and files within the included folder, and then to unhide them. I use this method when newly added items are not being displayed within the Library and periodically for all media Libraries to ensure consistency. If, after hiding files and folders, you are unable to see them to change the properties back to unhide, please follow previous instruction to 'show hidden files and folders'
Detailed instruction:
- Using Windows Explorer, click 'Computer' and navigate to the location of the Library (included folder/s).
- Right click the folder and select properties
- Under 'Attributes' check the 'Hidden' tick box. Press Apply
- When prompted, choose the 'Apply changes to this folder, subfolders and files' radio button. Press OK
- After attributes have been applied, unselect the 'Hidden' check box and hit apply again.
- Choose 'Apply changes to this folder, subfolders and files' and press OK
- Press OK to close out of properties.
All content should now be visible in the Library. Pip Pip, Hurray!
If this method does/does not work for you please drop a post and let me know!
Pau(L)