Bitmap File Format
BMP used to be only used within windows but is now a common format for other platforms. This is the standard format for storing bitmap images in windows applications. Sometimes known as device-independent bitmap (DIB) this format is also used by OS/2 programs and was used by many DOS applications. Graphics files include bitmap files, icon-resource files and cursor-resource files.
There are four Bitmap-File Formats. Windows bitmap files are stored in a device-independent bitmap (DIB) format that allows windows to display the bitmap on any type of display device. The term “device independent” means that the bitmap specifies pixel colour in a form independent of the method used by a display to represent colour. Each bitmap file contains a bitmap-file header, a bitmap-information header, a colour table and an array of bytes that defines the bitmap bits. The bitmap-file header contains information about the type, size and layout of a device-independent bitmap file. The bitmap-information header specifies the dimensions, compression type and colour format for the bitmap.
The colour table contains the same amount of elements as there are colours in the bitmap. The colour table for bitmaps with 24 colour bits is not required because each pixel is represented by 24 bit red-green-blue (RGB) values in the actual bitmap data area. The colours in the table appear in order of importance this assists a display driver to render a bitmap on a device that cannot display as many colours as there are in the bitmap colour table.
Each scan line of the bitmap consists of consecutive bytes representing the pixels in the scan line in left to right order. The number of bytes representing a scan line depends on the colour format and the width in pixels of the bitmap. The scan lines in the bitmap are stored from the bottom up. This means that the first byte in the array represents the pixels in the upper-right corner of the bitmap. Unlike other image-file formats like GIF and JPEG the BMP file format was not designed to be portable. Instead it was designed to easily work with the windows API using the same structures that windows applications use to manipulate in-memory bitmaps. As the API was updated so was the BMP file format.
Free Jpeg Images, view the free jpeg galleries containing many
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View the free colourful galleries containing sharper digital pictures. Interested in image file formats then check out this section for descriptions of the popular file formats that are being used.
Jpeg compression provides an efficient way to reduce the file size of an image. One of the benefits of this is the reduced download time of the pictures.
Depending on compression settings when the picture is saved a greater or lesser amount of detail will be in the image. Image file size is therefore a compromise especially on the internet.
View the free colourful galleries containing sharper digital pictures. Interested in image file formats then check out this section for descriptions of the popular file formats that are being used.
Jpeg compression provides an efficient way to reduce the file size of an image. One of the benefits of this is the reduced download time of the pictures.
Depending on compression settings when the picture is saved a greater or lesser amount of detail will be in the image. Image file size is therefore a compromise especially on the internet.
