Question regarding Banners

Hello everyone I am using media buying as an affiliate marketer. While doing competitive intelligence I have found some pretty awesome banners. I would like to know if it is possible to use these banners for my campaigns(I know it's not legal maybe)? Has anyone here have any experience regarding this? And how to do it safely. Or should I change some colors in the banner to make it a different one?

its not legal.

But i think you can create your own banner base on what you saw. and adding your own touches to it. Just make it different.

You can change the some effects and colors of the banners to use them more reliably.
It'll affect your working.

I beleive you should try and come up with an even better banner than you saw. You can use the colors and the layout because noone can own a color. However be aware of using images / icons / objects that could be the property of the advertiser behind the banner.