Here is a copied message I sent to another member who asked for help posting pictures:
This is the way I do it (from a PC, not sure how it works from a mac):
Find the image you want somewhere on the internet. Right click on the image, then click on "copy image location".
Now, go to where you want to post the image. Click on the "insert image" icon on the CB menu. It looks like this:

Now click paste and the hyperlink to your image should pop in between the two image commands. You should be all set from there.
Let me know if that works.