I've noticed that some JPG files are not displaying correctly when the container field has Optimize for (JPEG, PNG..etc) selected. If the selection is changed to optimize for interactive content, the JPG displays correctly.
Noticed the display problem under both a Window's client and a Mac client.
Sample is from Filemaker Adv 14.0.2
under Mac OS X 10.11
Database is hosted on OS X 10.10.5
running Filemaker Server 18.104.22.168
I have attached a screen shot of the container under both selections and a copy of the JPG.