If you want to protect your banners or anything else you created, you should first have the website, company, whatever else you are promoting approve the marketing item if it contains *anything* they might have already copyrighted, trademarked, or service marked.  

Once they have cleared it, then you will need to add a Copyright character or graphic [see example below] to your banner or other advertising materials.  This won't stop people who don't care about the rules, but it will stop the majority of people. 

Without any copyright notice within the marketing materials themselves, you would have a very difficult time trying to stop people from using your materials as their own. Honest people of course won't consider stealing your work and would instead reach out to you, and ask for your permission to use your stuff.  

I have included a standard Copyright notice at the bottom, that is used for written items such as this post.  It ensures that no one can just take what you have written, and then post it, publish it, or whatever else with your creation.  These days you have to protect yourself all the time, so always include a Copyright ©️ character or a Copyright notice within your works.  

If you have created something cutting edge that could have significant financial value, there is one more step you MUST take:  Print out a copy of every iteration / version  of what you created.  Put this into a 9x12 envelope and send it CERTIFIED Mail with "return receipt".  By using certified mail, you'll have independent validation of when you created it.  The return receipt gives you the date it was delivered and signed for.  You can sign for it yourself, it's not the signature that matters the most but rather the third-party aka independent verification regarding the date.  For very significant potential income a document could generate, you'll need to use the more expensive "REGISTERED MAIL",because it is tracked at every step along the way and every person that handles it must sign, date and time when they handled it.  It's more expensive, but it also gives you more proof from multiple independent third-party people when it went through the Postal Service mail stream.  Of course you can also use FedEx, UPS, DHL, and other shipping / logistics companies to handle the item,  but then you need to pay extra for the signature at delivery.  You can use their "track my package" feature to show the package tracking number and where it was at specific dates and times.  To make this information relevant,  you must also have a picture of the document or whatever it is, the shipping package as well as the shipping label that shows the from & to information, as well as the tracking number.  

If you have reason to believe that you will need to prove when you created this item multiple times, then you will need to send it to yourself however many times you believe you will need to be able to prove it.  Although once you have proven it and it is a matter of court record that you did create the item first, it will always remain a matter of court record.  But there are US Courts and there are European courts,  Asian courts, and so forth, so it is very plausible that you would have to prove that you were the first to create it in multiple jurisdictions.  You have to decide how valuable it is, and how much you are willing to invest in the beginning to document your creation.  If you have something that can potentially generate millions in profits, then spending a few hundred or even a couple thousand dollars to have 10, 20, or 30 copies of your creation with the date verified by one of the vendors such as I suggested OR any other vendor who can provide the proof of delivery with date and signature included. 

Ideally you will need to use "tamper evident" tape to seal your envelope, package, box, etc.  This specialty product, tears apart when you try to open anything that has it.  This will prove further that the contents of what you mailed / shipped have not been altered, because they will see that the tamper evident material is undamaged and therefore it has it's original seal intact.  I realize this is an expensive method of proving when you created something, but if you don't spend the money now to generate that PROOF - you will LOSE your creation when a company with expensive lawyers takes you to court claiming you are infringing on their copyrighted work.  If you can hand your attorney one of these envelopes / packages however,  it won't matter how great or expensive their lawyers are because you will have incontrovertible proof that you were the one to create it.  

Now that you have created these items and they are properly prepared and mailed or shipped, you need to have a means of storing them in DIFFERENT and SECURE locations.  A safe deposit box is a great place to put envelopes, but not packages and you can rent safe deposit boxes easily in multiple banks.  You should keep one copy in your house,  in a safe that is anchored to the house  AND that is fire rated to survive st least 1 hour and is either a 'composite fire safe' or a 'burglar fire safe'.  These types of safes offer protection against damage from fire and from burglary.   There are specific types of ssfes that can protect hard drives,  thumb drives, and other types of storage media.  Usually it is best to put this specialty safe inside a larger more typical safe.  Many people purchase a 'gun composite fire safe' or 'gun burglar fire safe' for their main safe, even if they don't have guns or only a few for protection.  The gun safes typically have the largest interior capacity. 

Take your time and do your due diligence, so you can feel comfortable, and confident that the safe you purchased will protect your valuables.

(  ©️  ) <--- example inside parentheses

Copyright ©️ 2020, Neal Brown. All rights reserved worldwide.