jAlbum does not have a way of extracting a still image from an externally-hosted video to use to create a thumbnail for it. You can use a video editing program to extract a single frame, take a screenshot, or choose any other still image to represent the video in the album. This should be a full-sized JPG image, rather than a thumbnail.
Add the image file that represents the video to the project.
Because the video must be connected to a single image, you cannot use album-level settings. You must choose the settings for this video under Image & Folder Settings. jAlbum cannot determine the dimensions or the length of an externally-hosted video, so these values should be entered manually. Enter the absolute URL for the video.
For a YouTube video, view the video on the YouTube site, click the Share button, and copy the URL that is displayed. Then click the Embed button, and make note of the width and height of the video. If there is no Embed option, that means that the person who posted the video does not allow it to be embedded on any other site, and you will not be able to use it in your album. The skin will accept either of the following URL formats:
The skin will still recognize the following formats, but these should not be used going forward. Support for them is not guaranteed, particularly the first format, which is for the obsolete YouTube Flash player:
For a Vimeo video, view the video on the Vimeo site, and click the Share button, and copy the URL that is displayed. Then click the Embed box, and make note of the width and height of the video. If you see a warning about domain restrictions on embedding, that means that the person who posted the video does not allow it to be embedded on any other site, and you will not be able to use it in your album. The skin will accept either of the following URL formats:
Enter the dimensions for the video in the image and folder settings. You can display the video larger or smaller than its native dimensions, but you should preserve the aspect ratio. If you don't, the video will be displayed with colored bars above and below the video, or on its sides.