How to bring back the default banner image in LinkedIn

LinkedIn Email Signature - No Longer Supported

Customized email signatures can no longer be created on the LinkedIn site. However, you can create an auto-signature from within your email client, and then direct your contacts to your customized public profile URL. Learn how to customize your profile URL.

You can customize your public profile URL when you edit your public profile. Custom public profile URLs are available on a first come, first served basis.

1. Move your cursor over Profile at the top of your homepage and select Edit Profile.
2. You'll see a URL link under your profile photo like www.linkedin.com/in/yourname. Move your cursor over the link and click the Settings icon next to it.
3. Note: "Update your public profile settings" will show up if you don’t have a public profile.
4. Under the Your public profile URL section on the right, click the Edit icon next to your URL.
5. Type the last part of your new custom URL in the text box.
6. Click Save.

Notes:

• Your custom URL can have 5-30 letters or numbers. Don't use spaces, symbols, or special characters.
• We recommend using a variation of your name and/or your professional brand since you’ll share this URL with people so they can find your LinkedIn profile. Some job applications may also ask you for your LinkedIn profile URL.
• The customizable part of the URL is case insensitive. This means using JohnSmith, johnsmith or johnSmith will all point to the same profile.
• If the URL you want isn't available, please select a different one. We can't make custom URLs available to members upon request.
• You can change your URL up to 5 times within 180 days. Once you have changed your URL for the 5th time, you won’t be able to change it for another 180 days. Changing your URL several times may make it hard for people to find you.
• If a member uses a URL and then changes it, that URL will be unavailable for use by other members for 180 days.
• If you navigate to a previously claimed URL, you may see a page that reads Profile Not Found.

Have a look at this FAQ entry

Currently, there's no way to change the default language of your profile once you've set it up in a particular language. Many people who speak multiple languages choose to create a secondary profile for each language. Viewers will see your profile in the language most relevant to them. All language profiles will show up in search engine results on and off LinkedIn and can be accessed directly with a unique URL.

You could also close your account and re-open one in your preferred language. We don't recommend this option, because you'll lose all of the connections and recommendations associated with the closed account

So you can't change it.