The image list is displayed in the upper right area of the Paint.NET window. A thumbnail is displayed for every image that you have opened, and allows you to switch between images quickly by clicking on the thumbnail.
To switch to an image, just click on it. You can also use Ctrl + Tab to switch to the next image in the list, or Ctrl + Shift + Tab to switch to the previous one. If there isn't enough room to show all of the open images, a black arrow will show up at either side of the image list. These arrows act as buttons that allow you to scroll left and right. You can also scroll through the image list by placing the mouse cursor in the image list area and then using the mouse wheel.
The white arrow at the left of the list is displayed when at least two images are open, and when clicked it will display a scrollable list of all the images along with their filenames.
You can also press Ctrl + Q to open this list.
You can close an image by clicking on it and then clicking on the 'X' that appears in the upper right corner of its thumbnail area. This is a convenient shortcut for the File → Close menu command
You can also use the Ctrl + W or Ctrl + F4 keyboard shortcut.
When an image has unsaved changes, it will be displayed with an orange asterisk in its upper-left corner.