Attention: Please read the Frequently Asked Questions if you have a question about usage rights.
The FAQ contains many examples on what is allowed with the images on Goodtextures.

If you still have any questions after reading the FAQ please don't hesitate to email: support@goodtextures.com

Email is checked throught the day and I will do my best to give a speedy response to each and every question. Goodtextures is based in Europe, keep in mind there might be a time zone difference.