Thank you for your post.
I am unable to replicate the issue, either by storing as reference or embedding. I have several EPS files that I have duplicated and changed the extension EPS to EPSF, and all images, EPS or EPSF, are inserted as pictures.
I would like to see one of your EPS files so I can determine why it is failing to insert as a picture. Check your Inbox at the top of this page for instructions where to send the file.
I received your file, but I initially was unable to replicate the issue. I say "initially", because although the file showed .epsf extension, the actual extension of .eps was hidden. That is, filename.epsf.eps.
Once I removed .eps extension, I was able to replicate the issue.
After talking with Testing, they pointed me to FileMaker Pro help and the topic "Using data in container fields", where it only lists .eps file extension for encapsulated postscript files. I have submitted the file extension .epsf as a feature enhancement for a future release. For now, you will have to replace the .epsf file extension with .eps.