Operating System Version? Filemaker Version? Local or network database?
Adding photo how? (there are 3 ways) DId this ever work properly? What has changed?
I too have just encountered this issue where inserting an image on the network had been working before, but now gets the 'file locked' warning. This happened after upgrading to Yosemite (osx 10.10) on the client computer.
The host computer hasn't changed (osx 10.8 whatever its name was), Filemaker 10. Client is filemaker 11.
To complicate matters, I am using a plugin (media manager) to handle image insertion. Images can still be inserted on the host machine without problem.