Vivienne [Genesis] - Recommended Image Sizes

Featured Image Size

For your featured images, images must be at least 800x1100px, but no larger than 2400px. This size will ensure your images display correctly in all areas of the theme (front page, blog page, category pages, etc).

Post Image Size

The width of the blog post column is 800px. For the clearest possible display, we recommend uploading images roughly twice that width (1600px is great).

If page speed is a concern, you can upload images right at 800px, but your images may be fuzzy on retina devices. Larger images don't really affect page speed all that much, unless you have an excessive number of images in one post.