What is the PNG file format?
A .png file contains raster graphics compressed with a lossless method using the Deflate algorithm. The format supports an alpha channel for transparent pixels and stores up to 16 bits of color data per channel - enabling 48-bit color in RGB mode or 64-bit color in RGBA mode. Each .png file holds a single image; the format does not support animations. The APNG and MNG formats are used for animated images derived from the PNG design.
The file starts with a fixed 8-byte signature (89 50 4E 47 0D 0A 1A 0A). The non-ASCII first byte and the CR-LF sequence serve as intentional corruption checks that detect 7-bit transfers and incorrect line-ending conversions. After the signature, the file is organized into named blocks called chunks, each carrying a specific type of data. A .png file can store:
- RGB graphics
- RGBA (RGB with alpha transparency)
- ICC and ICM color profiles
- EXIF metadata
PNG was created in 1995-1996 as a patent-free alternative to .GIF and is endorsed by the W3C as a standard format for distributing images on the web. RFC 2083, which specifies the PNG format, was published in 1997; the ISO/IEC standard (ISO/IEC 15948) followed in 2004. PNG is widely used for sharing images and is suitable for print output, although it is not used in professional print workflows because it supports only the RGB color model and not CMYK. PNG files are supported by virtually all web browsers and image editing programs.
Security & safety
RISK: LOWA PNG is passive image data and safe to open in any modern, updated viewer. Two caveats: historically, malformed images have triggered bugs in image-decoding libraries, so keep your OS/viewer updated; and PNG metadata chunks (tEXt) can carry hidden text, while the format can be abused for steganography - but a PNG cannot execute on its own. A file named "photo.png" that is actually an EXE would still need to be run as a program; the PNG itself is not a malware vector.
Format details
in a nutshellFULL NAMEPortable Network Graphics
DEVELOPERPNG Development Group (W3C / ISO standard)since 1996 (created as a patent-free replacement for GIF)
CATEGORYRaster Image Files
MIME TYPEimage/png
TYPERaster image, lossless compression (chunk-based binary)
STANDARDOpen · royalty-free
MAGIC BYTES · FILE SIGNATURE
OFFSET
0001020304050607
HEX
89504E470D0A1A0A
ASCII
·PNG····
Fixed 8-byte signature: 89 50 4E 47 0D 0A 1A 0A. The non-ASCII 0x89 first byte and the CR-LF / EOF bytes are a deliberate corruption check (detects 7-bit transfer and bad line-ending conversion). Immediately after the signature comes the IHDR chunk (width, height, bit depth, color type). The file always ends with an IEND chunk.
Programs that open PNG files
Windows4 apps
GIMP
Open-source Open for full editing; File → Export As to save PNG to other formats, with control over transparency. 
Photos / Paint (built-in)
Built-in Double-click to view in Photos; open in Paint to crop/resize and re-save. 
macOS2 apps
Preview (built-in)
Built-in Double-click to view; Tools → Adjust Size and File → Export to convert to JPG/other formats. 
Linux2 apps
Image viewer (Eye of GNOME / gThumb)
Open-source Double-click to view in the desktop's built-in image viewer.
Web2 apps
Web browser
Free Drag the PNG into any browser tab to view it - PNG is natively supported everywhere. Technical details
deep spec| MIME type | image/png |
| File signature | 89 50 4E 47 0D 0A 1A 0A - fixed 8-byte magic at byte offset 0 |
| Compression algorithm | Deflate (RFC 1951) wrapped in zlib (RFC 1950) |
| Compression type | Lossless only - pixel values are preserved exactly |
| Supported color modes | Grayscale, Indexed (palette), RGB, RGBA |
| Bit depth | 1, 2, 4, 8, or 16 bits per channel depending on color mode |
| Maximum color depth | 64-bit RGBA (16 bpc × 4 channels); 48-bit for opaque RGB |
| Alpha transparency | Full alpha channel: 8-bit or 16-bit per pixel |
| Interlacing | Optional Adam7 two-dimensional interlace scheme for progressive display |
| Pre-compression filter | Five adaptive row filters: None, Sub, Up, Average, Paeth |
| File structure | Sequential named chunks: IHDR → one or more IDAT → IEND |
| Embedded metadata | ICC/ICM color profiles, EXIF, text annotations (tEXt, iTXt, zTXt chunks) |
| Color calibration | gAMA chunk stores display gamma; cHRM chunk stores chromaticity data |
| Palette support | Optional PLTE chunk - up to 256 indexed color entries |
| Animation | Not supported in the base format; APNG adds multi-frame capability |
| Print color model | RGB only - CMYK is not supported |
| Released | 1996 (created as a patent-free replacement for GIF) |
| Open standard | Yes · royalty-free |
| Specification | www.w3.org |
PNG conversions
Possible
.PNG .WMFOnline converter
How to convert
.PNG .WBMPOnline converter
How to convert
.PNG .PBMOnline converter
How to convert
.PNG .PSDOnline converter
How to convert
.PNG .JP2Online converter
How to convert
.PNG .PPMOnline converter
How to convert
.PNG .EPSOnline converter
How to convert
.PNG .TIFFOnline converter
How to convert
.PNG .PGMOnline converter
How to convert
.PNG .TGAOnline converter
How to convert
.PNG .DIBOnline converter
How to convert
.PNG .EXROnline converter
How to convert
.PNG .EMFOnline converter
How to convert
.PNG .JPFOnline converter
How to convert
.PNG .JPGOnline converter
Yes - open the PNG in Paint, Preview, or IrfanView and save as JPG.
How to convert
.PNG .HDROnline converter
How to convert
.PNG .JPXOnline converter
How to convert
.PNG .DDSOnline converter
How to convert
.PNG .PDFOnline converter
Yes, you can convert PNG to PDF - the fastest way on any OS is to open the file and print it to a PDF printer.
How to convert
.PNG .WEBPOnline converter
Yes - PNG converts to WebP directly; the fastest way is dragging the file into Squoosh in a browser tab.
How to convert
.PNG .ICOOnline converter
Yes, PNG converts to ICO directly -- IrfanView does it in two clicks.
How to convert
.PNG .BMPOnline converter
Yes, any image editor handles it - on Windows the fastest way is to open the file in Paint and save it as BMP.
How to convert
.PNG .GIFOnline converter
Yes, PNG can be converted to GIF - the fastest way is ImageMagick on the command line or GIMP on the desktop.
How to convert
.PNG .SVGOnline converter
Yes, you can get an SVG from a PNG - but it is vectorization (redrawing as shapes), not a format conversion,…
How to convert
Community Q&A
asked by users
L
Frequently asked questions
How do I convert a PNG to JPG?
Open it in any image app (Windows Paint/Photos, macOS Preview, IrfanView, GIMP) and use Save As / Export to JPG. JPG is smaller but lossy and removes transparency - transparent areas turn white. For many files at once, batch-convert in IrfanView.
Does PNG support transparency?
Yes. PNG has a full alpha channel, so pixels can be fully or partially transparent - that's why it's the standard for logos and graphics over a background. JPG cannot do this; export to PNG (or WebP) to keep transparency.
How do I convert a PNG to SVG?
There's no direct conversion: PNG is pixels and SVG is vector paths. You vectorize (redraw) the image with Inkscape's Trace Bitmap or Illustrator's Image Trace. This works for simple flat logos and line art, not for photographs.
Why is my PNG file so large?
PNG is lossless, so it doesn't throw away detail the way JPG does - great for quality, bigger for photos. For photographic images use JPG or WebP; for graphics, run the PNG through an optimizer (TinyPNG, pngquant) to shrink it without visible loss.
How do I make a PNG with a transparent background?
Erase or select-and-delete the background in an editor (GIMP, Photoshop, Photopea), then export as PNG - PNG preserves the transparency. Many 'remove background' web tools also output a transparent PNG.
What's the difference between PNG and JPG?
PNG is lossless and supports transparency (best for logos, screenshots, graphics with text); JPG is lossy with no transparency but much smaller (best for photos). Re-saving a JPG degrades it; re-saving a PNG never does.
References
1W3C - Portable Network Graphics (PNG) Specification (3rd ed.)www.w3.org
2MDN - Image file type and format guide (PNG)developer.mozilla.org
