The application “Messages” does not have permission to open “IMG_5651.JPG.”

I use Messages to communicate with friends and family, and often images are sent back and forth. On my phone, it's no issue. On my MacBook Pro (early-2011), it has never been an issue prior to updating to Yosemite.

If an image is sent to me from a contact, the notification shows the image but won't display the image within the message thread.

In the thread it shows a white bubble with the file name.

If I right click on this little bubble, this is the menu that comes up.

If I select "Open" I am greeted with this message.

Selecting "Save to Downloads" does nothing. The file was not in my Downloads folder. This also happens when I send a photo/video from my phone or computer. However, if I send something from my computer, it shows on all devices. You can see where this is frustrating.

I've checked the permissions on everything, it seems like it all checks out and I decided to be safe and change anything that was "Read Only" to "Read and Write" just in case, but nothing. I've verified and repaired permissions twice in Disk Utility. I've tried changing the save location of files in the Messages app preferences. Nothing has worked. Any ideas as to what to do? Nobody else I know has this issue.

(Otherwise, I'm pretty in love with Yosemite. I love the new design of the Messages app and I can't wait for 8.1 to roll out tomorrow so I can use SMS.)