1. Launch the coverflow app.
2. Insert usb card reader and press the 'Refresh' button
3. Select the drive letter of the card you wish to use. At this point, the app will search your entire card for .nds files. This may take a little time, depending on how many files are on the card.
4. Once the file list is loaded, you may select any of the files in the list. The cover art window will show the cirrently assigned art for that file. If there is no cover art asigned, or you wish to change the current art, press the 'browse' button.
5. You can now select an image to use as that files cover art. You may also copy+paste the url of an online image.
6. Now, your new cover will be assigned. The image conversion will take a couple of seconds, slightly longer if your image comes from the web (download time of the image).