1. Left click the picture or text to be copied. This will highlight it.
2. Go to the toolbar above the message section of your Reply Box, and left click what looks like two pages. This has now copied to your mouse.
3. Open your Reply Box and click what looks like a clipboard with a piece of paper in front of it, next to the two pages, in the toolbar, and whatever you copied, will be displayed in your Reply Box.
If you can change fonts, change their sizes, change their colours, then you will certainly be able to do copy and paste.