This dialog box is shown when a new canvas (an empty bitmap) is created.
Predefined Image Sizes
This combo box allows you to select from a number of predefined image sizes.
Width & Height
These type-in boxes set the X and Y image resolution.
This type-in box specifies the DPI (dots per inch) resolution. This is typically 72 for screen based images. The DPI setting is typically only important if you are going to print the image or use it in page layout. The DPI setting describes how large the image will appear in print.
This combo box specifies the color depth. 8 bits provides a grayscale image, 24 bits provides a full color RGB image (this is the typical setting) and 32 bits provides a RGB image plus alpha channel.