I guess you know how to upload pictures to your website by now.

Here's a quick reminder:

Click on "Add Media"

Select or upload image:

Now, lets see how it's done on Youtube:

Important! Before you can upload your thumbnail to your channel you have to verify your Youtube account.
It will not work without the verification (thanks to SheilaN3 for pointing that out).

Go to your video manager and click on the video you want to add your thumbnail to:

On the right of your video you can choose between thumbnails and upload your own thumbnail.

Important Note! Your video has to be uploaded already to be able to do this! Just don't make it public before you have added the thumbnail.

You have created and uploaded an awesome thumbnail now! Time to make your video public!

This was my little thumbnail training. I hope you enjoyed it.
Let me know if this was helpful for you! :)

Moritz

Attention!

Read on to learn how to capture a screenshot from your Youtube video: