frostbytes,

Using Photos without the owner's authorization will be copyright infringement.

You'll get in trouble with the owner, in addition, AMZ will close your account for
TOS violation. Won't be the first time. There's only two ways to do it right:

1 Ask permission from the owner.
2 Use your own photos. Personally, I think is the best option:

You're differentiating yourself from the rest of sellers.

Meharis

Hopefully you are selling your own products which means that you should simply take your own photo of your product that you are selling. I have talked to someone before that wishes to have a more professional photo taken to list on amazon and the best thing to do is to make sure you make a nice background if you can. Hope this helps

You can't use images from anywhere else unless you have permission to use them from the owner of the images, regardless of whether there is a watermark on them or not—they simply aren't your property and copyright infringement is serious stuff.

Definitely take your own and make them brilliant—6 Ways Focusing on Images Can Increase Sales Online | RepricerExpress

This goes for your product descriptions too—don't just copy and paste manufacturers' descriptions into your listings—make them unique and sell the benefits of the product, not just its specifications.