Last week I finished a project with thousand images (few hundreds megabytes which is basically unimportant) when I suddenly realized that almost each image file is way larger than it is necessary. For example why I should use a 150×150 image as a 50×50 sideshow thumbnail? Plus there was one more resolution for featured images. So I decided to add those two dimensions to optimize page load speed – this was the easy part. Assuming you’ve already faced with this story you might know that adding new image resolution will not generate new images automatically.