First negotiate to the palette of your choice.
Select the option circled in red.
Choose save it and save the picture to your computer. Remember where you put it!
You will have this type of picture on your computer.
Upload the picture into your message post by using the 'Host an Image' button at the top of your message. Copy the Image address.
Open the 'Link' button that looks like an infinity symbol. Paste just the portion from the opening Img tag to the closing Img tag of the address for your picture in the lower input field called 'Label'. Paste the address for your palette at Colour Lovers in the upper input field called 'URL'.
When done it will look like the above and will link to your palette. This is what the code should look like.
I hope this is clear enough. If you need further explanation I'll answer any questions.