Thank you for posting.
I'll need some additional information to help you.
Since you have been able to paste pictures into your FileMaker file before, and now it isn't working, what has changed?
Are you able to create a new FileMaker file, create new records and copy the pictures successfully?
Is FileMaker hanging only when you do the copying of pictures, or have you needed to reboot for other reasons as well?
Are the file types that you are copying the same, that is, are they all "picture.jpg" or "picture.png"? Are you using the same source files?
Have you tried using a backup copy of your file from a time prior to this problem occurring?
Have you tried recovery on the file?
Container fields are limited to 4 gigabytes of data, so the size of your file should not be an issue.
Any details you can provide may assist in narrowing down the cause of this issue.