According to US copyright law, a photographer receives copyright at the moment of fixation on either film or memory card. If you have combined two or more of your own photographs on your computer you own copyright to that image as soon as you save that file. Copyright owners maintain the copyright for life + 70 years; in Mexico it is for life + 100 years.
Please note that it is not necessary to use the © notice on photographs. Under an amendment to the copyright law of 1986, images are protected regardless of whether you use this formal notice or not.
As of June 21, 2017, we ask that you respect not only the copyright laws but also the copyrighted owner of all the photographs that are published on and on all of our social media including Facebook, TwitterInstagram and Pinterest. 
We require you to contact us directly to use any of our photographs and thank you in advance for your cooperation.
Susan Knight York