Thank you for your post.
I am unable to replicate the issue. Here are the steps I took:
1. Using FileMaker Pro 13.0v1 under Mac OS X 10.9.1, I created a database file TSGal.fmp12.
2. I created a Text field, Names.
3. I created a Container field, Picture.
4. Under Option for Picture, I clicked the "Storage" tab and checked the option "Store container data externally.
5. Below that, I changed the option to "Open Storage" and let it default to "TSGal/Picture/".
6. I entered the first record where I entered "TSGal" for Name, and dragged an image into Picture.
7. I entered two more records, each time dragging an image into Picture.
8. I pulled down the File menu and selected "Save a Copy As..."
9. I let the file name default to TSGal Copy.fmp12, and at the bottom, I changed the Type to "self-contained copy (single file)".
10. I connected an iPad to the Mac, launched iTunes, selected the iPad in the left pane, clicked the Apps tab, scrolled to the bottom and clicked "FileMaker Go". On the right side are the files currently in the FileMaker Go work area of the iPad, where I then dragged "TSGal Copy.fmp12" into the file listing.
11. I launched FileMaker Go, tapped "Device", and opened "TSGal Copy". All three records exist with the images.
Let me know what I'm doing differently than you so I can replicate the issue.