Add your APNG file
Drop one or more .apng files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Converting a .apng image to .pgm re-encodes the pixels for a different balance of size, quality, and support. Free, private, and validated — the file never leaves your browser.
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.Converting a .apng image to .pgm re-encodes the pixels for a different balance of size, quality, and support. An .apng file is an animated extension of PNG: full 24-bit color with 8-bit alpha per frame, in a stream that plain PNG decoders read as a normal still image. It delivers the smooth, semi-transparent animation that GIF's 256-color palette never could, and it is the format behind many messaging-app sticker packs.
A .pgm file is a Portable Graymap: a single-channel greyscale image storing one intensity value per pixel, with the maximum value declared in the header. It is the middle rung of the Netpbm ladder — richer than a one-bit bitmap, simpler than a colour pixmap. For this route the practical draw is raw samples in a declared range — no codec, no colour management, nothing to misinterpret and supports 16-bit depth, which most consumer formats do not — balanced against uncompressed, so files are large relative to PNG for the same data, which is worth knowing before you commit a large batch.
The practical trigger for this conversion is usually a mismatch: with .apng, files grow quickly for long or high-motion animations, where animated WebP/AVIF or video compress far better. Switching to .pgm buys you raw samples in a declared range — no codec, no colour management, nothing to misinterpret, which is why it is the better fit for machine vision and image-processing pipelines that operate on intensity alone. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
| Aspect | Animated PNG (.apng) | Portable graymap (.pgm) |
|---|---|---|
| Format type | Lossless — every pixel or sample is preserved exactly | Lossless — every pixel or sample is preserved exactly |
| How it stores data | adds three chunk types to PNG: acTL (animation control), fcTL (frame control), and fdAT (frame data) | p2 stores samples as whitespace-separated ASCII integers; P5 stores them as raw bytes |
| Strongest at | animated stickers (Apple's iMessage and LINE both build on APNG) | machine vision and image-processing pipelines that operate on intensity alone |
| Weak spot | files grow quickly for long or high-motion animations, where animated WebP/AVIF or video compress far better | uncompressed, so files are large relative to PNG for the same data |
Drop one or more .apng files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Select .pgm in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if PGM is selectable, the route is real and validated.
Press Convert. Decoding and re-encoding happen on your device using the browser's native image pipeline and hand-tuned encoders.
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid PGM file. Outputs keep the original filename with the .pgm extension.
Since apng is lossless-oriented and pgm is lossless-oriented, the conversion preserves the source content exactly as stored; no additional compression pass is applied beyond what .pgm itself requires.
Yes — the .apng file is processed inside your browser tab and never uploaded. Decoding and re-encoding happen on your device using the browser's native image pipeline and hand-tuned encoders. Close the tab and the file is gone from memory.
Standard in scientific and machine-vision toolchains — OpenCV, ImageMagick, MATLAB and Netpbm all read it — and absent from consumer software and browsers. Novus Convert decodes both ASCII and binary PGM locally, honours the declared maximum value when scaling to 8-bit output, and converts to the standard raster formats.
It depends on the content: p2 stores samples as whitespace-separated ASCII integers; P5 stores them as raw bytes. Convert one representative file first and compare before batch-processing a large set.
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .apng → .pgm → .apng is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.