This dialog is intented for editing of image collection.
Button allows you to select file in BMP, JPEG (JPG), GIF, ICO, PCX, PSD, PNG, or TGA format to add it to the image collection. Button deletes selected image from the image collection. Buttons and move selected image up and down in the list of images.
allows you to select file in BMP, JPEG (JPG), GIF, ICO, PCX, PSD, PNG, or TGA format to add it to the image collection.
deletes selected image from the image collection.
and 
move selected image up and down in the list of images.