PNG and BMP are among the most frequently encountered image file formats when working with images. However, choosing the format that suits specific users’ needs can be difficult in the digital space.
This article discusses what links or separates PNG vs. BMP in terms of performance, transparency, image quality, storage requirements, file size, compression technique, animation support, structure, and browser support.
When is PNG better than BMP?
PNG files are losslessly compressed using LZ77 algorithms and Huffman coding, making them significantly smaller. BMP images are uncompressed and info-rich, resulting in larger files than PNG; this makes PNG files suitable for web-based uses compared to BMP files.
Why PNG? It supports alpha channel transparency, has a high color depth of up to 24 bits, and enables editing, which enhances its web optimization and user experience compared to BMP.
When is BMP better than PNG?
BMP images are detailed and of higher quality than PNG images. BMP stores all image colors without compressing any information, ensuring its files retain their full details and quality. This makes them suitable for medical imaging, design, and graphics, as they provide precise image details as required.
The pros of BMP images include the ability to be edited severally without losing image quality; simple pixel sequences, each with color data stored directly in the file; and ease of writing and reading using most applications.
BMP versus PNG Table Comparison
| Variable/Factor | BMP | PNG |
| Transparency | Does not support alpha channel transparency | Supports for alpha channel transparency |
| File Size | Larger files than PNG | Smaller files than BMP files |
| Image Quality | Slightly higher quality images than PNG images | High-quality images, although lower quality than BMP |
| Performance | Low web responsiveness than PNG. | High web responsiveness than BMP. |
| Structure | A raster-based format with a header, information header, pixel data, and color table. | A raster graphics format with an 8-byte header and multiple chunks. |
| Animation | Does not support animation. | Does not support animation. |
| Storage | Requires more storage space compared to PNG. | Requires less storage space than BMP. |
| Compression | It is uncompressed but supports lossless compression with RLE. | Compressed and supports lossless compression with Huffman coding and LZ77 algorithms. |
| Browser Support | Widely supported by popular browsers. | Widely supported by popular browsers. |
Differences and similarities between PNG and BMP images
PNG and BMP are versatile file formats similar in lossless compression, animation, and browser support.
An analysis of PNG versus BMM found notable differences in file size, transparency support, image quality, structure, storage requirements, and web performance.
Transparency
A BMP does not have inherent support for transparency. BMP file format lacks advanced features or support layers that enable it to support transparency. However, it promotes additional color spaces and alpha channels.
In contrast, PNG supports grayscale images and alpha channel transparency, enabling more image manipulation freedom. It is easier to use alpha channel transparency in PNGs if a singular theme has well-defined margins and a large block of adjacent space, such as an icon or logo.
File Size
PNG files with identical image contents will be significantly smaller than BMP files. Both formats preserve as much image information and details as possible, although PNG files are automatically compressed.
PNG files allow for further compression using Huffman coding and LZ77 algorithms, making them smaller than BMP files. Conversely, BMP files are uncompressed but support lossless compression with Run Length Encoding algorithms, resulting in larger files than PNGs.
The BMP file format has a maximum file size of 4GB due to its use of 32-bit unsigned integers to store file size information. BMP files store uncompressed image data, resulting in larger file sizes than PNG files, which use lossless compression. In most cases, PNG files are significantly smaller than BMP files for the same image, although there can be exceptions for simple images.
Image Quality
When deciding between PNG and BMP files, consider the size and quality of an image to make a cognizant decision. PNG is a high-quality image format, just like BMPs, although it uses compression. PNG works better for simple embedded graphics, comic strips, line drawings, logos, and icons.
Conversely, BMP stores all image colors or details without compressing any information, ensuring its images or files retain their full details and quality. This benefits technical drawings or digital art requiring high levels of detail.
Performance
The losslessly compressed PNG images are significantly smaller than the uncompressed BMP images. As a result, the larger BMP files slow down website loading time while smaller PNG files increase web responsiveness. The smaller PNG sizes enhance webpage loading times, save bandwidth, and improve user experience compared to BMP files.
Structure
Both PNG and BMP are raster graphics file formats. However, they hardly compare in terms of structural design. PNG has a fixed number of pixels and boasts variable transparency, cross-platform image brightness control, and two-dimensional interlacing.
The structure of a PNG file starts with an 8-byte magic identification signature. The header is closely followed by three or more dissimilar chunks comprising uniform syntax. Conversely, the BMP’s header contains info regarding file size, type, and the Device-autonomous bitmap file layout. The information header specifies the BMP file's color format, compression type, and dimensions.
PNG’s IDAT chunks can hold compressed image data. All chunks tend to conform to a defined structure. Still, every chunk has a private identification consistent with its inner format, read serially from the start to the end of the data stream, unlike BMP’s pixel data, which consists of various bytes defining its bits.
A PNG file has critical chunks supported by all file readers and writers. In contrast, BMP stores bitmap digital images independently based on the display devices, including the graphics adapter. It includes the actual data characterized by successive scan lines. Every scan line comprises continuous bytes representing the pixels in the row in a left-to-right sequence.
The BMP system maps the pixels starting from the bottom row of the rectangular area and ending with the top row or scan line. Every scan line appears to be zero-padded to the closest 4-byte boundary. Therefore, gauging both file formats' structural designs, it is difficult to compare BMP and PNG’s structure.
Animation
Both PNG and BMP do not support animation. While PNGs do not support animated content or animation, their specifications are extended in APNG, which supports animation by introducing animation control chunks.
In contrast, BMP hardly supports animation, but digital bitmap images allow for manipulation and editing using software and the outcome used in creating animations. All BMP file pixels can be allocated a specific color value and utilized to create animations in other image formats that support animation.
Storage
BMP images are uncompressed, while PNGs lossless compress automatically. Hence, BMP files are larger than PNG files. When different BMP files are pooled together, they consume more space and memory. Thus, the smaller file sizes of PNGs necessitate less storage space and less bandwidth than BMP.
The uncompressed and losslessly compressed BMP files are stored indefinitely in Device-Independent Bitmap formats (DIB). PNG stores lossless compressed data forever in Content Delivery Networks(CDN), Cloud, Base64 encoding, and file systems.
Compression
Typically, BMP image data remains uncompressed. Nevertheless, when considered crucial, the file format uses lossless compression with a run-length encoding (RLE) algorithm to compress 4-bit and 8-bit bitmaps.BMP’s lossless compression can be in either an encoded or absolute mode, resulting in higher-quality images than PNG images.
PNG uses the non-patented DEFLATE lossless file compression method. DEFLATE uses different compression algorithms, from 0 for no compression to 9 for complete compression. The PHP GD default application selects the algorithms that combine Huffman coding and LZ77.
Browser Support
PNG is a recent next-gen file format, while BMP is an older and established image format. BMP is widely supported by almost all browsers, including Internet Explorer, Safari, Discord, Edge, Vivaldi, Chrome, Opera, and Firefox.
On the other hand, PNG is compatible with and supported by modern browsers, including Chrome, Opera, Safari, Firefox, and Edge. The Internet Explorer and older browsers do not support it.
Converting PNG to BMP or BMP to PNG
Using convertjack to convert PNG to BMP is much easier than you think. Users prefer BMP because it is information-rich, uncompressed, and preserves all image information. Owing to their preciseness, BMP images are ideal for medical imaging.
Users would want to use a BMP to PNG converter called Convertjack because it is user-friendly and quickly converts a BMP to PNG. The resulting PNG images are significantly smaller than BMP, high-quality, support alpha channel transparency, and enhance web responsiveness, making them suitable for web graphics, illustrations, logos, charts, and architectural blueprints.