You can also import images by selecting them in the file explorer and dragging and dropping them onto Nebulb.
Or it is also possible to select a folder in the file explorer, drag it directly onto Nebulb and drop it, so that all images contained in that folder will be loaded.
Once all the images have been imported, Nebulb will display the image selected as the base image (which is always the one that is temporarily in the middle) and in the "Import Images" section you can see the summary information of the imported images.