Do you need Permission?
You need permission for any of the following:
you are planning to use artwork, photograph or drawing that is protected by copyright
you use a significant part of an artwork, photograph or drawing
the copyright has not expired yet (expired 50 years after the copyright owner passes away in most cases)
the way you are using the artwork, photograph or drawing is controlled by the copyright owner, If you are using the copyright work is outside the scope of the usage agreement, you will need to contact them.
Are there any free images?
Just because you found it on Google Images - does NOT mean you are free to use it. Images on Google image searches are covered by international copyright law and thus it is not a "free for all." Some designers, photographers, artists and typographers offer “free” licences to use their material but it is important to be aware however that these works are still subject to conditions including attribution (crediting the artist) or for personal/student use only. Please read the terms and conditions before using anything from the web.
You are liable if you supply Killer Aesthetic with any files with copyright restrictions.