When is PNG better than ICNS?
PNG images are detailed and highly compatible with most software and operating systems. In contrast, ICNS images are mostly used for macOS icons and are not typically compatible with non-macOS software and programs.
PNG files are high-quality and support more color profiles than an ICNS, making them ideal for creating graphics, comics, logos, charts, and web illustrations. Given their spectacular visual appeal, quality, and widespread browser support, PNG images are also great for creating web illustrations.
When is ICNS better than PNG?
ICNS images are scalable but ensure image quality and a high-resolution level, while PNG images are non-scalable and become indistinct or pixelated when scaled upwards or downwards. As such, ICNS images are suitable for creating visually distinct images, desktop shortcuts, and application icons.
The pros of ICNS images include high-resolution and high-quality images with upward and downward scaling, smaller file sizes, which increase web responsiveness, and flexibility since the file format incorporates multiple images with varying sizes and color depths, resulting in visually striking icons.
ICNS versus PNG Table Comparison
| Element | ICNS | PNG |
| Transparency | Supports alpha channel transparency | Supports alpha channel transparency |
| File Size | Smaller than PNG | Larger than ICNS |
| Image Quality | Limited color support; Scalable up and down while preserving image quality and resolution levels. | Info-rich/detailed and high-quality images with outstanding visual sharpness and crispiness. |
| Performance | Smaller images that load faster than PNG. | Larger images that load slower than ICNS. |
| Structure | It starts with a header and ends with binary icon data. | Starts with an 8-byte signature and ends with many chunks. |
| Animation | Supports animation or animated images. | Does not support animation or lively content |
| Storage | Smaller single icons or multilayer images necessitate less storage space than PNG. | Larger, detailed, or info-rich images necessitate more storage space than ICNS. |
| Compression | Uses PackBits compression method | Uses lossless compression with LZ77 and Huffman coding. |
| Browser Support | Limited browser support compared to PNG. | Supported by almost all browsers bar for IE6. |
Differences and similarities between PNG and ICNS images
PNG and ICNS are adaptable file types similar to transparency support. However, the two file formats significantly differ in browser support, compression methods, file size, structure, animation, image quality, storage, and web responsiveness.
Transparency
ICNS and PNG file formats support alpha channel transparency. For example, PNGs establish all pixels' transparency levels, ranging between transparent (0) and opaque (255). Its tRNS subsidiary chunk then manages PNG's transparent structure.
In contrast, the contents of an ICNS file usually comprise a single or more images in PNG format. The PNG file extension is handy as a base for the ICNS since it allows transparency. The ICNS file supports 1-bit and 8-bit alpha channels.
File Size
An ICNS file comprises a single or multiple icons with varying sizes and color depths, resulting in larger file sizes when pooled together. However, single ICNS files are smaller than PNG files. A PNG file has no size limit and can be as large as 140GB or more.
On the other hand, an ICNS file has a maximum size limit of 33 KB, although its size varies from 4 KB to 33 KB. ICNS files are MacOS X icon files comprised of unreadable, cryptic characters whose average size ranges from 26KB to 660 KB.
ICNS supports icons of 16×16, 32×32, 48×48, 128×128, 256×256, and 512×512 pixels. ICNS further supports larger images, including 1024x1024 pixels, while PNG's maximum file dimension is 2G x 2G pixels.
Whereas ICNS and PNG are raster-based files, PNGs are not scalable, while ICNS files can be scaled up or down to fit different screen sizes without losing quality or resolution levels. Thus, while a single PNG file is larger than an ICNS file, ICNS files pooled and stored together can be larger than 140GB PNG files.
Image Quality
PNG and ICNS are high-resolution and high-quality file types. However, ICNS files have limited color depths compared to PNG files. The ICNS files support a maximum color depth of 8 bits per alpha channel. They can be scaled without losing image quality, while PNGs become blurry with downward or upward scaling.
While ICNS's color depth is suitable for designing various icons, it is hardly sufficient to create highly detailed or information-rich icons. It supports IHDR, ARGB, and RGB color profiles. Its limited color depth compels designers or web developers to use the high-color-depth, detailed, and data-rich PNG image format.
PNG is a low- and high-resolution, high-quality file format that supports 24-bit RGB or 32-bit RGBA color space, which gives it a better quality standard than ICNS files. PNGs support 256 quantized palette colors, although its TrueColor file supports 16 million colors.
Performance
A single ICNS file is comparatively smaller than a PNG file. An ICNS can be 33kb to 660 kb, while a PNG file has no size limit. As such, a PNG file loads slower on websites than an ICNS file, increasing user experience and producing an optimized search engine than a PNG.
Conversely, multiple ICNS files pool together images of varying color depths and sizes compared to the pixel-based PNG files, increasing their general file size. While multiple ICNSs are larger than a PNG file, they may require higher bandwidth and decreased web responsiveness.
Structure
ICNS and PNG are raster-based file formats. However, comparing both formats in terms of structure is not easy. ICNS file's structure includes a header and binary icon data. The header has 8 bytes of data, four of which are the magic literal and four of which are the file's length.
The size and type of every ICNS icon image are stored in the icon data section, followed by the binary image data. The image size determines the size of the binary section.
In contrast, a PNG file structure begins with an 8-byte magic identification signature, closely followed by three or more chunks containing uniform syntax. The multiple PNG IDAT chunks are compactly held in the compressed image information.
Each PNG chunk conforms to the defined structure, and its identification corresponds to its inner format. The chunks are read serially from the start to the end of the data stream or file. A PNG file has critical chunks that each writer and reader must support.
Animation
A PNG file does not support animation, while an ICNS file supports animation. An ICNS file contains icon features, which enable websites or computer applications to be customized to support multiple color depths and resolutions, allowing for animation or lively content.
Conversely, while PNG files do not support animations, their specifications can be extended in APNG file format, which supports animation by integrating the animation control chunk. Nonetheless, animated PNGs are smaller, color-rich, detailed, and visually attractive than animated ICNS.
Storage
Single ICNS files compressed and stored using PackBits algorithms are smaller than lossless PNG files. As such, ICNS files necessitate less storage space than PNG files. Conversely, multiple ICNS files stored in icons for programs, files, and folders can be comparatively larger PNG files and require more bandwidth.
ICNS and PNG files can last indefinitely when appropriately handled and subjected to good storage conditions and the proper storage medium. ICNS files can be stored in icon directories, folders, content delivery networks, hard drives, the cloud, and the package's Contents or ​Resources directory.
Conversely, PNG files can be stored in the cloud in Base64 encoding, file systems, hard drives, floppy drives, DVDs, CDs, and content delivery networks.
Compression
PNG compresses images using the non-patented DEFLATE lossless compression. DEFLATE uses diverse compression algorithms, from 0 to 9, which denote uncompressed and fully compressed, respectively. The PHP GD default application selects the algorithms that combine Huffman coding and LZ77.
The chosen algorithms recreate the primary image precisely. The PNG compression occurs in two phases: filtering and compression. During filtering, PNG uses delta encoding for every scan line of pixels. The pixels are programmed based on the pixels above the left, the pixels above, and the pixels to the left.
The resultant PNG file is passed to DEFLATE, which combines Huffman coding with the LZ77 algorithm—the DEFLATE compression results in the compressed PNG image file. In contrast, an ICNS file format supports lossless compression of certain sections of the pixel data.
The ARGB and 24-bit RGB pixel data are compressed per channel with a format similar to PackBits. Each ICNS image file consists of a single string of pixels, consuming memory space. The ICNS's PACKBITS algorithms depend on run-length encoding (RLE), which is meant to shrink file sizes.
Under this compression technique, redundant ICNS file information that exists as repeated data is represented concisely. The PACKBITS algorithm encodes the redundant ICNS data by storing series (runs) of identical pixel color, resulting in higher-quality files.
Browser Support
ICNS has limited browser support compared to PNG. It is supported by web browsers such as Chrome and Firefox but unsupported by Edge, Discord, Opera, Safari, Vivaldi, and Internet Explorer. Convert ICNS to PNG to enjoy high compatibility across web browsers, platforms, and programs.
On the other hand, PNG files are highly supported by different web browsers, such as Opera, Edge, Chrome, Safari, Firefox, Discord, Vivaldi, Internet Explorer, and Brave. Still, they are unsupported only by Internet Explorer 6.
Convert PNG to ICNS or ICNS to PNG
Convert PNG to ICNS to enjoy high-quality, high-resolution images and smaller, scalable files that can be displayed optimally without losing image quality. Convertjack helps users convert PNG to ICNS easily.
Conversely, Convertjack, an ICNS to PNG converter, readily helps users convert their ICNS files to PNGs to ensure they enjoy wider browser compatibility and detailed and data-rich files/images.