Yes, you can just open a web page in your favourite browser and then take a screenshot, with PrtScr. However, this will produce a non standardised output so if you want to use a number of screenshots in a gallery from different times they might all be different sizes.

Fortunately, Chrome has a feature that can assist with this as well as testing responsive web designs. Within in the Developer Tools, you can select Toggle Device toolbar. This toolbar then allows you to either select a standard device (e.g. iPad, Pixel 2 etc) or specify the width and height (e.g. 1080 x 800). Then select the More options menu and then Capture Screenshot.

You will now have an image, I then scale down the image using say Paint 3D (with Microsoft Windows).