I take a large amount of sports photos at the high school level of football and soccer. All images are clearly watermarked. The kids are taking screen shots from mobile devices to gain the image. Does anyone have any recommendations on how to solve this? 

 You might be able to set it in a preferences as "no mobile view" or something like that , so when they go on your site on there phones they can view your wbsite in a same format as on the computer. Let me know if it helped

my site: www.emmelephotograohy.com

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how to solve this? 

To solve what, exactly?

Anything that is viewed in a browser can be save, in fact it's already saved at the time of viewing it in the browser cache. Screen captures can be done on smartphones, and there are all kinds of photo editing app's out there to clean up the screen capture afterwards, so there is nothing that can be done about it other than water marking & maybe using smaller display sizes to discourage these people from saving them, you did mention the images are watermarked, maybe you could change the size of them or apply differently to again like I say discourage them from saving them.