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small (mobile phone)
medium (tablet)
large (desktop).
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Simple screen test
Once you have a draft preview link of your image within a content page, you can simply hover over the far right or left hand side of the browser and drag it inwards to see the tablet and mobile view.
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Accurate screen test
When previewing a front-end draft of your page, right-click on an empty area of the website and select Inspect > Inspect Element.
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