A featured image appears not only at the top of the article, but also as the card when the post is shared on social media, and in your blog's list of posts. Each time, it is cropped to a fixed ratio, so choose the size by asking whether the important part survives whichever ratio it is cut to. If you want a baseline, use 1200x630 pixels.
Why 1200x630 is the baseline
Facebook's developer documentation on images in link shares recommends using images of at least 1200x630 pixels for the best display on high-resolution devices. To get the display with a large image, you need at least 600x315 pixels; anything smaller is shown small. The smallest image allowed is 200x200 pixels.
1200x630 is a landscape ratio of about 1.91:1. Make the image at this ratio and it appears as a large card when the post is shared.
How much of a landscape image gets cut
The image you have will not necessarily be exactly 1.91:1. Our landscape assets are 1408x768 pixels (about 1.83:1). The frames below show what remains when one of them is cropped to other ratios. The darkened area outside the frame is what gets cut off.
1.91:1 is slightly wider than the image, so only a little comes off the top and bottom. As long as the person's head and hands are not close to the edges, it works as it is.
16:9 is slightly narrower than the image, so this time a little comes off the left and right. Again, it makes almost no difference.
Cropped to a square, a large part of the left and right is lost. Some blog themes show post thumbnails as squares in the list of posts, and then only the centre remains. If the main subject sits towards an edge, readers cannot tell from the list what the post is about. The surest option is to choose a featured image whose main subject sits near the centre.
If you overlay text, choose a composition with space
If you put the title over the featured image, choose a composition with an area of little detail. If the image may be cropped to a square, though, the text also needs to sit towards the centre, or it will be cut off in the list of posts. How to choose where text goes is compared, using slides as the example, in “Illustrations in training slides work best on the right pages”.
In-article images follow different rules
A featured image and an in-article image do different jobs. An in-article image only has to fit the width of the text and is never cropped, so square or portrait shapes are fine. Images that need to show detail, such as step-by-step diagrams, are easier to read as squares or portraits.
Watch the file size too
Correct dimensions do not help if the file is heavy: the page will be slow to display. When we measured three of our landscape assets, each came to about 65–210KB as WebP. The same picture as PNG is six to eight times the size. The measured figures for each format are in “What Is WebP? What to Do When a Downloaded Image Will Not Open”.
Sources
- Meta for Developers: Images in Link Shares
Information as of September 2026, when this article was written.