There are two possible reasons why the Report Title Page Image icon is greyed out on your customisation dashboard:

1. Your user role does not provide access to it. 
2. Your Plan does not provide access to it. 

For the former speak to the Account Admin of your account. If your plan does not include the Report Title Page Image functionality as standard, you can purchase this as a bolt-on to your subscription for an additional £5 per month. Please contact us for further information.