What are the 3 parts of a typical BMP image file?

The bitmap file header data structure, which contains information such as the type of BMP image file, display content, etc., and the bitmap information data structure, which contains information such as the width and height of the BMP image, compression method, and defining colors.

Often seen bmp image files are generally larger and take up a lot of space. This is because no compression is used except for the optional bit image depth.When a Bmp file stores data, the image is scanned in a left-to-right, bottom-to-top order.

Expanded Information:

BMP image file notes:

Users need to be aware that the member variable biHeight in the bitmap information header BITMAPINFOHEADER, which represents the height of the image, specifies whether the image is an inverted bitmap or forward oriented bitmap.

Users should note that if the value of biHeight is a positive number, the image is inverted, and if the value is a negative number, the image is inverted. Most BMP files are inverted bitmaps, which means that the height value is a positive number.

Since Windows does line scans in the smallest unit of 4 bytes, when the image width ? * number of bytes per pixel ! = an integer multiple of 4 to fill in the missing bytes at the end of each line with zeros.

Baidu Encyclopedia - BMP Format

Baidu Encyclopedia - Image Files