So we all know that a lot of communication is visual (and thanks to Dr. Merhabian, we know it’s 93% visual) so it makes sense that the photos on your site need to be right. You need to make sure you’re using the right type of image (.jpb vs .png vs .svg vs .bmp) and that the file size is not too big (slow load times = no bueno) and you need to make sure you’re offering an alternative image for different screen sizes.
Since people can look at your page with the image on it on various sized devices, you need to test it out and see how that picture of your dog wearing a scarf and sunglasses, or that burly worker restoring a brick wall, will look on a phone. If you don’t write some css specifying a different photo for that different screen size, your site will not come across as as well-made as you intend.
Sally wants us to remember to choose an image with the subject at the center. Then, no matter the size of the screen showing the image, the most important part of the photo is going to be shown.
“This is the simplest and least expensive way to ensure that your hero image works across multiple screen sizes–least expensive, because your designer only has to produce one crop of the image and your developer only has to code one set of media queries.”
Her second, more comprehensive but more tedious suggestion, is to go the “art direction” route, select different crops of an image for different screen sizes and/or orientations. ;
“The up side of art direction for your hero images is much greater control. The down side is that someone has to generate those different versions of your hero image and then code them.“
In Divi, say what you will about their shortcode clutter, but they handle this stuff for you a lot easier. I will explore that in a later edit to this post.