Convert PNG to APNG Online

Convert PNG to APNG: What This Tutorial Covers

APNG is animated PNG — the same file structure you already know, with extra chunks that hold a sequence of frames. It keeps full 24-bit colour and the full 8-bit alpha channel on every frame, which is the one thing GIF can never do. This page assembles a set of PNGs into that sequence. The critical thing to understand before you start: animation needs more than one image. Upload a single PNG and you get a static file back. Everything below assumes you are uploading a frame sequence.

How to Convert PNG to APNG

1. Upload Your PNG Frames: Drag your images onto the page or click "+ Add Files". Add them in playback order — that upload order becomes the frame order. Two frames is the minimum for a real animation.
2. Set the Framerate: Under "Video Framerate" the "Framerate" dropdown fixes how long each frame is held. "10 FPS (Recommended)" is preselected and writes a 1/10-second delay per frame; the list runs from "1 FPS (Slideshow)" up to "50 FPS (Max Speed)".
3. Choose Combine and Image Resolution: "Combine?" decides the output shape — "Single animation" (the default) merges every upload into one APNG, "Individual files" converts each one separately. Under "Image resolution", "Keep original" is preselected; switch to Preset Resolutions, Width, Height, Width × Height or Resolution Percentage to scale the frames.
4. Convert and Download: Click "Convert" and save the .apng. No sign-up, no watermark; files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours.

One Image vs a Sequence — What You Actually Get

In our testing, three 400 × 300 PNGs at the default 10 FPS produced a file whose acTL chunk read num_frames=3, num_plays=0 — zero meaning loop forever — with each fcTL carrying a 1/10-second delay, and the fully transparent corner pixels still reading as fully transparent in the output. The same run with a single image produced a file with no acTL chunk at all.

Walk-through: Framerate, Frame Order and Size

• Framerate is a per-frame delay, not a target playback speed. At 10 FPS every frame is held for exactly 1/10 s, so a 12-frame sequence runs for 1.2 seconds. Pick 25–30 FPS for fluid motion from a dense frame set, 5 FPS for a stepped, deliberate sequence, and "1 FPS (Slideshow)" when you want each picture to sit for a full second.
• Frame order is upload order. The assembler numbers the frames as it receives them, so name or add your files in sequence. There is no drag-to-reorder step after upload — reorder before you convert.
• The loop is always infinite. APNG stores a play count in its acTL chunk, and this converter writes 0, which the specification defines as "loop forever". There is no play-count control on the page, so a play-once APNG is not something this tool can produce.
• Resize the canvas, not the frames. The APNG assembler cannot resize on its own, so the "Image resolution" setting is applied to the shared canvas that every frame is fitted onto. That means the same setting also normalises a mixed-size batch — set a Width or a Width × Height and every frame is scaled and centred into it.
• There are no quality or colour controls here. The compression group is hidden on this page: the convert path writes full-colour, full-alpha frames and then runs a Zopfli optimisation pass over the finished file. If you need a smaller APNG afterwards, the palette-reduction controls live on Compress APNG.

APNG vs GIF

Common Errors and How to Fix Them

• "My APNG doesn't animate." Almost always a single-image upload. One frame cannot animate — add the rest of the sequence and convert again.
• "The frames play in the wrong order." The order you added the files is the order they play. Remove them and re-add in sequence.
• "Some frames look offset or have empty space around them." Your sources are different sizes, so each was centred on the largest common canvas and padded with transparency. Crop or resize your frames to a consistent size first, or set an explicit Width × Height under "Image resolution".
• "It plays once and stops in my viewer." The file declares an infinite loop, so a viewer that stops after one pass is applying its own policy. Test in a browser rather than a desktop image viewer.
• "The file is bigger than I expected." Full-colour, full-alpha frames are simply larger than a 256-colour GIF. Reduce the canvas size, drop the frame count, or send the finished file through Compress APNG.

When This Doesn't Work

If you already have an animation and just want it in APNG form, this is the wrong page — converting a sequence of stills is a different job from re-timing an existing one. Use GIF to APNG to carry an existing animation across with its own frame delays intact, or MP4 to APNG to build one from video. And if the destination is an old email client, a chat platform that transcodes uploads, or anywhere you cannot control the decoder, GIF is still the safer bet despite its 256-colour ceiling — PNG to GIF covers that. Going the other way, APNG to PNG extracts a still and APNG to GIF downgrades the animation for compatibility.

Frequently Asked Questions

Why did my single PNG come back as a static image?

Because one frame is not an animation. The assembler duplicates a lone input to make a two-frame sequence, then notices both frames are pixel-identical and merges them back into one — which leaves a perfectly valid PNG carrying an .apng extension and no acTL animation-control chunk. That is the correct outcome for the input, not a failure. Upload the rest of your frames to get a real animation.

Does APNG keep the transparency from my PNG frames?

Yes, completely. APNG inherits PNG's 8-bit alpha channel, so every pixel keeps its exact opacity on every frame, and frames padded onto a shared canvas are padded with transparency rather than a solid colour. This is the main reason to choose APNG over GIF, which can only mark a pixel fully transparent or fully opaque and therefore leaves a hard fringe around soft edges, glows and drop shadows.

How do I control how long each frame stays on screen?

Through the "Framerate" dropdown, which is written into the file as a per-frame delay of 1 ÷ your chosen rate. At the default 10 FPS each frame holds for 1/10 second; at "1 FPS (Slideshow)" each holds for a full second. Every frame in a given APNG gets the same delay — this converter does not expose per-frame timing, so if you need one frame to linger, duplicate it in the upload.

Can I make the animation play a fixed number of times instead of looping?

Not on this page. The play count is written as 0 in the acTL chunk, which the PNG specification defines as looping forever, and there is no control to change it. If a play-once animation is a hard requirement you will need to author the file in a dedicated APNG editor.

Will APNG display everywhere, and what happens if it doesn't?

Roughly 95.9% of global browser traffic supports it — Chrome 59+, Edge 79+, Firefox 3+, Safari 8+ and Opera 46+ all animate APNG natively; Internet Explorer and Opera Mini do not. The failure mode is gentle: APNG's animation chunks are ancillary, so a decoder that does not recognise them skips them and renders the first frame as an ordinary PNG. Nothing breaks; the image simply stops moving.

Do my source PNGs have to be the same dimensions?

They do not have to be, but the result is cleaner when they are. Mismatched frames are each scaled to fit a shared canvas sized to the largest width and the largest height in the batch, centred, and padded with transparency — aspect ratio preserved, nothing cropped. If that produces empty margins you did not want, normalise your frames first or set an explicit Width × Height under "Image resolution".

Is APNG an official standard now, or still an extension?

It is official. APNG began as a Mozilla extension in 2004 and lived outside the spec for two decades, but the PNG Specification Third Edition became a W3C Recommendation on 24 June 2025 and folds the acTL, fcTL and fdAT chunks into the standard itself. The same edition adds HDR colour metadata. Files produced before and after that date are byte-compatible — the standard caught up with the format, it did not change it.

How many frames can I combine, and is there a size limit?

There is no fixed frame cap. The practical limits are upload size and time: a long sequence of large frames is a big upload, and every frame is stored at full colour with full alpha before the optimisation pass, so the finished file grows roughly in proportion to frame count × canvas area. If the result is too big, scale the canvas down under "Image resolution", cut redundant frames, or run the output through Compress APNG.

What happens to my images after the conversion?

They are uploaded over an encrypted connection, assembled on our servers, and both the uploads and the finished APNG are deleted automatically after a few hours. No sign-up, no watermark, and nothing is shared or made public.