Now that you know what pictures are important for your website and content, let's discuss the image sizes and orientation.
Locable's software will process all images that are uploaded to create multiple versions for use in different places - as a result, we generally recommend images are at least 1200px wide and 1-5MB in file size.
NOTE: The maximum image size is 5MB.
Sharing to Facebook and Responsive Images
According to Facebook's support pages at the time of writing, they recommend "Use images that are at least 1200 x 630 pixels for the best display on high-resolution devices."
If your image is larger that's fine, if the orientation is different then the image will be cropped.
While square and portrait images can be used, they simply don't give you as many options and often get cropped to fit the available space.
For instance, the hero image at the top of web pages, the main image on blog posts, event images, etc should all be landscape orientation. The hero, in this case, has different setting options and often will display slightly differently on different size screens as the page is responsive.
Sharing to Facebook
Also, if you find the wrong image is being displayed when sharing to Facebook you can have them recrawl your page by going to https://developers.facebook.com/tools/debug/ adding the specific URL and clicking Debug then rescrape.