There is a 3.9mb file size limitation on photo's been uploaded to the forums server
These are the error messages you will see depending upon how you upload the photo/s.
1. Uploading a single photo using the "Insert Image" icon
You will get this error message ( click on image to enlarge )
Error1.jpg
2. Uploading multiple photo's using the "Attachments Icon"
You will get this error message ( click on image to enlarge )
Error2.jpg