The words "Your Garage" are grey, but they're just noting a part of the menu. You want to click your vehicle name under "Your Garage" to get to your vehicle profile page. From there you want to click the badge icon under your Log Book.
It should update whenever you add or edit a fuel-up. If you're not seeing an updated version you might have the image stored locally in your cache. Even though we tell browsers not to cache these images in as many ways as possible, some browsers and networks are still aggressive about caching.
Go to the page where you're seeing the "old" image, and try a Ctrl + Shift + R. This will bypass the local cache in most browsers. If that doesn't work, take a look at these instructions for your specific browser.
No luck then? Try editing your latest fuel-up and give it another shot.