PNG / JPG / WebP, 3–8 images; order becomes the preview slideshow
Add screenshots to preview the cut.
Preview uses the scaled total length; Export builds the real MP4. Store pages often autoplay muted—keep captions readable.
What this tool does
App Store preview videos must be 15–30 seconds, ≤30 fps, and use Connect’s accepted sizes such as 886×1920 for current iPhone portrait—not screenshot sizes like 1320×2868. Google Play is different: Console takes a YouTube URL only, not an MP4 file. This tool turns 3–8 screenshots into a local slideshow with optional captions and crossfades, scales the cut into 15–30 seconds, and exports H.264 MP4 with silent stereo AAC via open-source mediabunny (MPL-2.0) + WebCodecs. Nothing uploads to our servers. It isn’t a full NLE and ships no music library (copyrighted audio can force ads on YouTube and break Play preview rules).
How to use
- Upload 3–8 PNG/JPG screenshots, drag to reorder, add captions and per-slide lengths as needed.
- Pick export size (default iPhone portrait 886×1920), total length 15–30s, fit mode, and optional fades.
- Export MP4, check the checklist, then download—upload to App Store Connect for Apple; for Play, upload to YouTube first and paste the URL.
FAQ
Are images or videos uploaded?
No. Drawing, encoding, and muxing run in your browser with open-source mediabunny (MPL-2.0) on top of WebCodecs. Screenshots never go to our servers.
Why 886×1920 instead of 1320×2868?
886×1920 is App Store Connect’s accepted preview resolution for current iPhones. 1320×2868 is a screenshot size. Mixing them often fails upload or lands in “A Closer Look.”
Can I upload the MP4 straight to Google Play?
No. Play preview video is YouTube-URL-only. Upload the MP4 to YouTube (public or unlisted, embeddable, monetization off), then paste the link in Play Console.
Why a silent audio track?
Apple expects a stereo audio configuration. We write silent stereo AAC so missing-audio rejects are less likely. Store pages often autoplay muted—put the message in on-screen captions.
Which browsers work?
You need WebCodecs H.264 (AVC) + AAC encode support—recent Chrome or Edge is recommended. If unsupported, the tool says so; Image to GIF can still demo motion, but GIFs aren’t valid App Store previews.
What open-source stack / license?
Muxing and encode orchestration use mediabunny (MPL-2.0). Commercial use is fine; file-level copyleft applies if you modify mediabunny sources. We use the stock npm package. License copy: /vendor/mediabunny/LICENSE.txt.
Related guides & tools
More tools in thedeveloper toolbox. For store preview shots, try theApp Store screenshot maker.