I want to test website for large screens such as 1920 x 1080 pixels, 2560 x 1600 pixels, In browserstack i find only 1280 x 1024 pixels is maximum for windows machines, Is there any website to test for large screen resolutions
Well you can easily do it in Mozilla Firefox.
Then you can choose from varieties of resolutions, also for your custom resolutions.
You can drag the sides to increase and decrease the resolutions.
Some links here on keyboard shortcuts and responsive design view
and the other on tilt which I guess you have it as an add-on and that is conflicting with the command.
For one time you you have to drag for custom 2560x1600 resolution and add it as preset. Then further you can always use this resolution settings.
I think if you test 2560 x 1600 pixels or wider pixels it will same for the Full HD resolutions that mean 1920x1080 , so your site is responsive and supports up to full HD no matter the how screen size changes. If you want to test in multiple devices, you can use a few testers and the Firefox browser mobile tester.
RESPONSIVE DESIGN TESTING TOOL - ("http://lab.maltewassermann.com/viewport-resizer/")