Facebook has updated their layout (again) and if it hasn’t been reflected in your News Feed yet, you’ll see it soon. With these less-than-slight size changes, you might need to change the pixel size in the images you’re sharing.
With the update, all images will now fit into a box no larger than 470 pixels wide and 394 pixels tall. Images will no longer be cropped. Instead, they are scaled down in size to fit into that box. However, no image will ever be shown taller than 349 pixels nor wider than 470 pixels. The ratio for well-sized photos is 235:197, which is super strange. However, a ratio of 4:3 is much easier to remember, and will work great. Even the Facebook-recommended 1:1 square images will not fit well within the redesign, at least in my opinion. So-called “portrait” images, those taller than they are wide, will be shown with even more whitespace surrounding the image.
Posts with links are very much the same, but with a few additional peculiarities. An image within a linked post will automatically be given a ratio of about 2:1 (1.91:1, exactly). These images must be at least 470 pixels wide and 246 pixels tall. Images smaller than 470×246 will be shown in a 150×150 box. Images smaller than 150×150 will be scaled down to 90×90 or not shown at all.
There are a multitude of options for editing your photos to the correct sizes. Along with popular (and expensive) options like Photoshop, there are evermore web and device based apps. This is especially convenient if you manage your social posts via a mobile device.