Help with Pic posting with Apple...

[Mojo]

I'm having a hard time posting a pic I want into a thread with my MacBook...
it's in jpeg format, 2.4MB size...I don't get it...I used to just browse and select and upload...what's the trick my fellow Mac users...I'm semi-new to the OS

[BrianG]

I export the photo from my library. Then do customized size. I always do 750 and it works.