We can capute screenshot in two formates.
1).jpg
2).bmp
selenium.capturescreenshot("path of file to store screenshot");
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int i=900;
selenium.capturescreenshot("path of file to store screenshot"+i+".jpg");
2).bmp
selenium.capturescreenshot("path of file to store screenshot");
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int i=900;
selenium.capturescreenshot("path of file to store screenshot"+i+".jpg");