PNG to SWF Converter

How to Convert PNG to SWF Online

1. Upload Your PNG Files: Drag and drop or click "Add Files" to select PNG images — screenshots, logos, exported UI mockups, sprite frames from Photoshop, or game assets exported from Aseprite. Batch is supported, and the order you upload becomes the slide order in the resulting Flash slideshow.
2. Pick Per-Frame Duration and Background (IMAGE_DURATION / VIDEO_BACKGROUND_COLOR): SWF wraps your PNGs as a timed slideshow. Set how long each PNG holds on screen — 1/60, 1/30, 1/24, 1/10 second for animation-style frame playback, or 1, 2, 3, 5, up to 10 seconds for slideshow pacing. Pick a background color (Black, White, Red, Blue, Green, plus 20+ named colors) for any transparent PNG areas, since SWF's FLV/Sorenson video layer doesn't carry an alpha channel.
3. Set Codec, Quality, and Resolution (Optional): Choose the internal video codec via VIDEO_CODEC — FLV / Sorenson Spark (the default and most Ruffle-compatible), or FLASHSV / FLASHSV2 (Flash ScreenVideo, lossless but less broadly supported). Pick a VIDEO_QUALITY_PRESET (Highest → Very High → High → Medium → Low → Very Low → Lowest), a VIDEO_FIXED_RESOLUTION_PRESET (1920×1080, 1280×720, 854×480, 640×360, 426×240) or label preset (1080p / 720p / 480p / 360p / 240p), and optionally use MERGE_VIDEO to either merge all PNGs into one SWF or emit one SWF per image.
4. Convert and Download: Click Convert. Files process in your browser session — no sign-up, no watermark, no upload to a third-party server.

Why Convert PNG to SWF?

SWF (Small Web Format, originally Shockwave Flash) was Adobe Flash's container for vector animation, web banners, and embedded media from the late 1990s through the early 2010s. Adobe officially end-of-lifed Flash Player on December 31, 2020, and Chrome, Firefox, Edge, and Safari all removed the Flash plugin in early 2021. PNG → SWF is therefore a niche, archive-only conversion — useful in a handful of specific legacy scenarios where a Flash projector or emulator is still the playback target:

• Flash slideshow recreation for legacy LMS courses — Articulate Presenter, Adobe Captivate, and Lectora courseware from 2005-2015 commonly embedded image sequences as SWF slideshows. If you're reauthoring a chapter of a still-Flash-based internal LMS, dropping new PNG screenshots into an SWF keeps the asset native to the course's Flash projector.
• Sprite-frame and animation cels for Flash games — Pixel-art games preserved through Ruffle or Flashpoint sometimes need replacement sprite sheets or splash frames. Converting a folder of PNG cels into an SWF at 1/24s per frame produces a Flash-native animation clip the game's ActionScript can load.
• Internal kiosks and signage running a Flash projector — Closed-network kiosks built before 2015 (museum exhibits, retail point-of-info, factory-floor terminals) often still run a Flash projector executable. Replacing a faded PNG ad reel requires SWF, not MP4 or PNG sequences.
• Standalone Flash projector (.exe / .app) playback — Adobe's standalone Flash Player projector still runs offline on Windows and macOS. SWF is the only format it plays. Useful for offline museum exhibits, historical software demos, and Flash-era portfolio archives that need to look authentic.
• Flash-era portfolio and artwork archival — Designers and illustrators who shipped Flash banner ads, intro splashes, or animated logos sometimes need to repackage modern PNG renders into the original SWF wrapping for portfolio completeness or Internet Archive submission.

For anything modern — websites, social media, mobile, email — convert PNGs to PNG to GIF, PNG to MP4, or PNG to WebM instead. SWF will not play in any 2026 browser without an emulator.

PNG vs SWF — Format Comparison

Per-Frame Duration → Playback Style

Frequently Asked Questions

Will the SWF I create play in a 2026 browser?

No — and this is unavoidable, not a tool limitation. Adobe Flash Player reached end-of-life on December 31, 2020, and Chrome, Firefox, Edge, and Safari removed the Flash plugin in early 2021. The only ways to play a SWF in 2026 are: Adobe's standalone Flash Player projector (still downloadable from Adobe's archives, runs offline), the Ruffle open-source Flash emulator (browser extension or desktop app), or Flashpoint (curated Flash game preservation project). For an animated PNG slideshow that actually plays on the modern web, convert to PNG to GIF or PNG to MP4 instead.

Will my PNG transparency survive into the SWF?

Partially. SWF supports vector-layer transparency, but the FLV / Sorenson H.263 video codec inside SWF — which is what your PNG slideshow gets encoded as — does not carry an alpha channel. Transparent PNG areas get composited against the VIDEO_BACKGROUND_COLOR you choose (default Black). If you need transparency preserved end-to-end, FLASHSV (Flash ScreenVideo) keeps a lossless RGB representation but still flattens alpha. Pick a background color that matches your target Flash project's stage color.

Should I pick FLV/Sorenson, FLASHSV, or FLASHSV2 as the codec?

FLV / Sorenson Spark (the default) is the most broadly compatible — every Flash projector since version 6 plays it, and Ruffle's video support targets it most reliably. FLASHSV is lossless and well-suited to UI screenshots and pixel-art with sharp edges, but only Flash Player 7+ projectors play it. FLASHSV2 is more efficient lossless but only Flash Player 9.0.115+ supports it and Ruffle's coverage is partial. For maximum reach, stay on FLV. For pixel-perfect screenshot reels going into a known-modern Flash projector, FLASHSV is the better pick.

What's the best per-frame duration for a Flash-style animation?

For frame-by-frame cel animation, use 1/24 second (the classic film-and-Flash standard) or 1/30 second for smoother modern playback. Older Flash banners and Newgrounds-era animation often ran at 1/12 second (12 fps) — pick 1/10 second for the closest match. For a photo slideshow rather than animation, 2-5 seconds per frame matches typical Flash slideshow pacing of the late 2000s e-learning era.

Can I merge multiple PNGs into one slideshow SWF, or get one SWF per PNG?

Both. The MERGE_VIDEO option (also called IMAGE_TO_VIDEO_MERGE_DEFAULT) controls this — leave it on to merge all uploaded PNGs into one timed slideshow SWF, or switch to per-file mode to emit one SWF per PNG (useful when each frame needs to be individually loadable in an ActionScript project). Upload order determines slide order in merge mode.

Why is the SWF so much larger / smaller than my PNG sources?

It depends on the codec and per-frame duration. With FLV / Sorenson at typical Flash-era bitrates, a slideshow of high-resolution PNGs is usually smaller than the sum of its source PNGs because the video codec's lossy compression aggressively trims detail (and visibly drops quality compared to the originals). With FLASHSV (lossless) and short frame durations, the SWF can be larger than the PNGs since it adds the SWF container overhead plus a per-frame keyframe. Downscaling resolution via VIDEO_FIXED_RESOLUTION_PRESET is the simplest knob for shrinking the output.

Does Ruffle play the SWF this tool produces?

Ruffle's video and image-layer support has improved significantly through 2025-2026. Ruffle plays Sorenson FLV inside SWF on most modern builds, which is why FLV is the default codec. FLASHSV / FLASHSV2 lossless screen video is partial — recent Ruffle builds handle FLASHSV but FLASHSV2 coverage is incomplete. For best Ruffle compatibility, stick with the default FLV / Sorenson selection, 480p or smaller resolution, and 1-5 second per-frame durations.

Will the SWF play on mobile?

No. Flash Player for mobile was discontinued in 2012 and never returned. iOS never supported Flash. The converter itself runs in any modern mobile browser, but the SWF output won't play on any phone or tablet without a desktop-class emulator. For mobile playback of a PNG slideshow, convert to PNG to MP4 or PNG to GIF instead.

Can I batch a folder of PNGs into one SWF for a Flash game's sprite sheet?

Yes — that's one of the best remaining use cases. Drop a folder of PNG cels (sprite frames, animation keyframes, UI states) in the order they should play, set IMAGE_DURATION to 1/24 or 1/30 second, leave MERGE_VIDEO on, and pick FLV as the codec. The resulting SWF can be loaded by an ActionScript loadMovie / Loader call inside a Flash game running under Ruffle or a standalone projector.