Slideshow Maker

Turn holiday photos, a product line-up, a class year or a stop-motion sequence into a video you can post or send. Choose the photos and, if you like, a song; set how long each photo stays, pick a transition, and the slideshow is built as an MP4 right in your browser with the ffmpeg engine (about 30 MB, downloaded the first time). Photos of any shape are fitted to 16:9, 9:16 or square on a blurred copy of themselves, a colour, or cropped to fill. Nothing is uploaded.

How to use this tool

1. Choose the photos in the order they should appear (or sort them by file name) and, optionally, a music file.
2. Pick the timing: seconds per photo, spread over the song, or photos per second for stop motion.
3. Choose a transition, the video size and how photos of another shape are fitted; tick the slow zoom for a Ken Burns look.
4. Press Calculate, watch the preview and download the MP4.

Formula

Video length = number of photos × seconds per photo (transitions overlap, so they add no time)

Each photo starts at k × seconds per photo; a transition begins at that moment and blends from the previous photo, so the total length stays exact. "Spread over the whole song" divides the song's length by the number of photos. Every time is rounded to whole frames at 30 fps (stop motion uses the rate you choose). Music that is longer than the slideshow is cut and faded out over the last 2 seconds; shorter music is repeated if you tick it.

Example

24 photos at 4 seconds each make a 96-second (1:36) slideshow. With a 3:12 song and "spread over the whole song", each photo gets 192 ÷ 24 = 8 seconds. As stop motion, 120 photos at 12 photos per second become a 10-second clip.

How long it takes

Every frame of the video is encoded in your tab on one processor core. Measured on a recent desktop computer, a 720p slideshow with crossfades takes about 7 seconds per photo (20 photos ≈ 2½ minutes), 1080p without transitions about 9 seconds per photo, and the slow zoom at 1080 × 1920 about 20 seconds per photo. Phones are slower. Keep the tab open while it works.