A BMP file or image is a raster graphics file format that stores bitmap digital images or pixel information as a sequence of bits. BMP stands for Bitmap Picture and is identified using the file extension “.bmpâ€.
The bitmap digital images are autonomous of graphics adapter and are similarly known as Device Independent Bitmap (DIB) file format. The autonomous nature of BMP files serves the tenacity of opening the images on different platforms, including Mac and Windows.
The file format can store information as 2D digital images in both color formats with varying color depths and monochrome. Unlike other file formats like ICO and ODD, the BMP format is simple and easily compatible with different software or programs.
BMP can be uncompressed or may use lossless compression, making it an information-rich file format with larger file sizes. Its files have large, raw, high-quality images, making them suitable for editing. The file format can store color data without any compression.
BMP files are simple to read because they store uncompressed data, unlike compressed GIF files, which are challenging to decompress.
History of BMP Files
Bitmap Picture (BMP) has existed since the earliest days of personal computing. Microsoft first introduced it with the Windows 1.0 operating system in 1985. However, Microsoft Corporation created and launched the universally approved version of the BMP format in the 1990s.
Over the past years, Microsoft has produced various revisions of BMP, adding new color modes and enhancing its ability to store additional data or info regarding an image. The first version was called BMP version 1.
The original version merely supported 1-bit color, equal to black and white formats. Nonetheless, Microsoft later created BMP version 2 when it released Windows 3.0. The improved version supported 8-bit color BMP images to contain a wide color range.
Windows NT 3.1 was released with BMP v3, incorporating run-length encoding bitmaps and true color (24-bits). It enabled the inclusion of different color ranges in BMP images and allowed the files to be compressed to minimize their sizes.
BMP v4 accompanied Windows 95, which allowed it to support more color space types and alpha channels. The latest version, BMP v5, launched with Windows 98, supports ICC profiles.
Thus, BMP was created to help store pixel-based images in a sequence, which allowed them to be readily displayed on computer screens. Despite its widespread compatibility and adoption, BMP is only used by 0.1% of all global websites.
Websites that currently use the BMP format include Live5news.com, Wafb.com, Easy-prace.cz, Cdslindia.co, and Mondo.rs.
Properties of BMP Files
BMP files can store 2D digital images in varying color depths and optionally with alpha channels, data compression, and color profiles. As a data-rich format, BMP structure is dictated by its bit depth, resolution level, file size, and whether it supports animation, transparency, resizing, editing, and compression.
Structure
BMP is a raster graphics image format that stores bitmap digital images independently depending on the display devices, including the graphics adapter.
The BMP structure comprises a header, information header, color table, and pixel data. A BMP header contains information regarding file size, type, and the Device-autonomous bitmap file layout. The corresponding bytes for a BMP header are 0x00 – 0x0D.
The information header specifies the BMP file's color format, compression type, and dimensions. The corresponding bytes for the BMP information header are 0x0E – 0x35.
The color table comprises as many bitmap elements as colors within a BMP file. However, bitmaps with 24 color bits hardly have a color table since 24-bit RGB values represent every pixel in the actual bitmap information region. The equivalent bytes for the color table are 0x36—variable.
The pixel data comprises various bytes defining the BMP bits. It includes the actual data characterized by successive scan lines or rows of the BMP. 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.
BMP files are usually larger since they preserve more image information. They are suitable for creating detailed images without artifacts but with crisp edges. The number of bits per pixel, including 1, 4, 8, 15, 24, 32, or 64, for any bitmap file is indicated in the file header. The most common BMP files are 24 bits per pixel.
The BMP image format comprises uncompressed data, making it ideal for storing and displaying high-quality images. The file format supports multiple color depths, ranging from simple 1-bit monochrome images to 4-bit (16 colors), 8-bit (256 colors), 16-bit (65536 colors), and 24-bit true color (16.7 million colors) images.
BMP files can store indexes in color tables—a BMP file using 24 bits per pixel stores colors independently instead of indexes in a color table. In principle, BMP images can contain up to 64 bits per pixel, with image size restricted merely by the file size. It hardly supports multi-sample pixels.
Besides being a temporary or intermediate format in the Windows application context, BMP is applicable primarily for small images where high-bit depth is not deemed necessary. Bit depth dictates the quality and resolution level of a BMP image.
BMP is a high-quality image format with a maximum amount of details. It supports ICC profile and over 16.7M colors by mixing 256 tints of Blue and Green with 256 shades of Red. BMP has a maximum file size of either 32,767×32,767 or 2,147,483,647×2,147,483,647 pixels, which largely depends on the format version.
It is equally a high-resolution format. Its high-quality and detailed files allow BMP to retain full image details and quality, making it suitable for high-resolution images. Nevertheless, to maximize image quality, BMP images must be 1200 PPI.
Typically, BMP files created for professional printing are 300 dpi and above, while bitmaps generated for desktop printing or printers usually are 150 dpi. Web-based BMPs are 72 dpi, and bitmaps developed for computer monitor displays are 72 or 96 dpi.
Storage
BMP files or images are stored in Device-Independent Bitmap formats. The file format stores uncompressed data to ensure image quality by preserving color panels or dimensions.
The BMP format can store data as 2D digital images in monochrome and color formats with varying color depths. The file format requires a large storage space to accommodate its larger file sizes.
BMP image data are stored in the cloud, file systems, the Content Delivery Network (CDN), or hard drives (HDD). Depending on the handling and conditions the files are subjected to, BMP files or images can last forever.
Compression
Generally, BMP image formats are uncompressed. However, when deemed necessary, the file format uses lossless compression with a run-length encoding (RLE) algorithm to compress an 8-bit bitmap. BMP lossless compression can be in either absolute or encoded mode.
In an encoded compression mode, the first byte specifies the number of successive pixels to be drawn using the color index contained in the second byte. The first byte can be zero, indicating the escape character, which signifies the end of the line, a delta, or the bitmap end based on the second byte's value.
In the absolute mode, the first byte must be zero, while the next is a value between 03H and FFH. The second denotes the number of bytes that follow, each containing the color index of a single pixel.
If the second byte appears to be two or below, the escape contains identical meaning to the encoded BMP mode. However, in the absolute mode, each run-length encoding should be zero-padded to the end on the 16-bit word boundary.
During RLE lossless compression, BMP files can be smaller but retain all image details, including the number of color planes, size, and type or number of bits per pixel. The file format recovers all image information when uncompressed, although variable compression is impossible for BMP files.
4-bit and 8-bit BMPs can be compressed. The simple Run Length Encoded (RLE), instead of storing a value for each pixel, RLE stores a number, N, followed by an index. The order implies that the next N pixels are of the color for this index.
BMP compression is necessary to balance image quality and size. It also moderates the memory and disk storage required for the bitmap. Compressed and uncompressed BMP files are larger, increasing website loading time.
Editing
The uncompressed nature of the BMP files or images makes it easy to edit them using photo-editing software like Corel PaintShop Pro, Paint.NET, CorelDraw, Microsoft Paint, GIMP, and Adobe Photoshop.
A BMP image can also be resized using Microsoft Photos, illustrator, Paintbrush, MS Paint, Adobe Photoshop, CorelDraw, and GIMP.
Animation
BMP does not support animation. However, digital bitmap images can be manipulated and edited using software programs and used in animations. Each pixel in a BMP file can be assigned a particular color value and used to create animations in other formats that support animation.
Transparency
A BMP does not have inherent support for transparency. The file format lacks advanced features or support layers that enable it to support transparency. However, it promotes additional color spaces and alpha channels.
Best Use Case of BMP Files
- Suitable for design and graphics: BMP is ideal for displaying and storing icons, logos, illustrations, and photographs in graphics and design fields because it offers high-level details and precisely represents complex images.
- Suitable for Website Design and Optimization: BMP images enhance the visual appeal of websites, attract users' attention, and convey information effectively.
- Suitable for SEO and Marketing: BMP files create engaging multimedia content, online advertisement, and compelling social media posts.
- Suitable Imaging: BMP preserves all image information, making it ideal for medical imaging as it gives precise details as required.
Unrecommended Use Cases of BMP Files
- Unsuitable for Bigger Projects: BMP's larger file necessitates more storage space and is suitable for bigger projects with limited storage spaces.
- Limits Web Speed: BMP is unsuitable for Websites that value faster loading times because the uncompressed files or images reduce web responsiveness.
BMP Browser Support
BMP files or images are widely supported by browsers such as:
Google Chrome
Mozilla Firefox
Microsoft Edge
Internet Explorer
Opera, Safari
Discord
Vivaldi
IE6 was found incompatible with BMP but added features make the browser compatible with the file format.
Possible BMP Browser Errors
- Many applications opened on your PC to load your BMP image format file successfully.
- Hardware related to BMP has device driver corruption
- The BMP is infected with a virus
- Your BMP file is corrupted
Advantages of BMP
- Detailed and High-Quality: 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.
- Simple Structure: BMP comprises a simple sequence of pixels, each with color information stored directly within the file. Thus, BMP files are easily written and read using most applications.
- Uncompressed Format: BMP stores uncompressed color data, making it easy to edit and resave its files several times without losing image quality.
Disadvantages of BMP
- Large File Sizes: BMP stores uncompressed color data, making its files larger, particularly for high-resolution images. This makes it challenging to manage large projects with limited storage space.
- Limited Features: BMP hardly supports transparency or multiple layers, standard features in advanced file formats such as PSD or PNG. The lack of such features limits BMP's functionality and versatility in some apps.
- Deficient Universal Support: Although widely supported, BMP is not universally supported. Some less common or older devices and platforms face difficulties displaying or reading BMP files, limiting their accessibility and usability.
How to open a BMP File
A BMP file or image can be opened using Microsoft Photos, Preview, illustrator, Paintbrush, MS Paint, XnView, Adobe Photoshop, FastStone Image Viewer, Irfan View and GIMP.
On the other hand, the file format (BMP) is compatible and supported by most operating systems such as macOS, Linux, Android, GNOME, Microsoft Windows, AmigaOS 4, iOS, OS/2, AROS, and Morphos.
Converting a BMP File
Use online BMP converters such as “Convertjack†to convert your BMP file to ICO, FLV, DOCX, GIF, DOC, EPS, AVI, 7Z, 3GP, AAC, GIF, PDF, SVG, PNG, JPG, and TIFF.