ideenic has made a good point which I forgot about.
It is true, many websites now use a data scheme or a data attribute in their HTML source code of a web page to embed images, and "data attributes" tend to include various script methods. This can make downloading the image problematic. So, if the standard "right-click / save image as" command does not work, then take a screenshot and extract the specific image from the screenshot using an image editor like MSPaint, saving the image using the common format of JPG or PNG.
To see what ideeinc speaks about, you can read more here: