In the main picture above, you can see how the image is used in different ways on the home page of your site - depending on the style of your home page.
The image above shows:
- a 'main picture' being used as a full screen display
- several 'main pictures' being used as links to the detail page, in 2 different layouts
'A picture is worth a thousand words' - so make sure that your picture is eye-catching and relevant for the content of the page. You want it to encourage visitors to look at that page.
Guidance for 'main' pictures:
- Landscape (wide) format pictures work better than portrait (tall).
- Most cameras give a 3:2 ratio picture; stick with this. I recommend that images be 1200px x 800px.
- If you can't match these sizes, be consistent and try to use the same size picture for each page - this will keep things nicely aligned, without distorting images.
- Use .jpg/.jpeg or .webp format pictures. These are compressed format, so don't take as long to download as a .png, for example. (webp is a fairly new format and is not supported in iPhones/iPads before 2020, which may be a considertion for you)