The ability to display images on screen is one of the most important features of a Vulkan's swapchain--and, in fact, it's what a swapchain was designed for. In OpenGL, when we finished rendering to a back buffer, we just switched it with a front buffer and the rendered image was displayed on screen. We could only determine whether we wanted to display an image along with blanking intervals (if we wanted a v-sync to be enabled) or not.
In Vulkan, we are not limited to only one image (back buffer) to which we can render. And, instead of two (v-sync enabled or disabled), we can select one of more ways in which images are displayed on screen. This is called a presentation mode and we need to specify it during swapchain creation.
