Sample .bmp files

FileZigZag is an excellent online image conversion service, using which you can convert a BMP file to any popular image format. This program is very user-friendly. To get the format you need, just upload your file and select the source image format. I also recommend using Zamzar online converter if you want to convert a BMP file in a quick way. You can change the BMP format to any of the popular formats without downloading the software.

BMP is a popular format for saving raster images. It is a unique format because it stores color data for each pixel of an image without any compression.

However, in rare cases, you can come across compressed BMPs. Lossy compression formats are usually suitable for photographs. BMP is a format developed by Microsoft for Windows. When you break an image into a grid of thousands of squares, you get a bitmap image.

Each square contains color data and displays a color based on that data. Since we use pixels to form images, we must convert files to a bitmap file format first. Each scan line is zero padded to the nearest 4-byte boundary. If the image has a width that is not divisible by four, say, 21 bytes, there would be 3 bytes of padding at the end of every scan line. Instead of storing a value for each pixel RLE stores a number, N, followed by an index.

This means that the next N pixels are of the color for this index. These are the actual image data, represented by consecutive rows, or "scan lines," of the bitmap. Each scan line consists of consecutive bytes representing the pixels in the scan line, in left-to-right order. The system maps pixels beginning with the bottom scan line of the rectangular region and ending with the top scan line.

Horizontal width of bitmap in pixels. Bits per Pixel used to store palette entry information. This also identifies in an indirect way the number of possible colors. Lets have a look at some of these in detail, especially the headers. A Bitmap File Header is similar to other file headers used to identify the file. All integer values are stored in little-endian format. The detailed information about the image is represented by this header. Based on this information, application will be determined that will be used to display the image on the screen.

All such headers contain a DWORD bit field, specifying their size, so that an application can easily determine the header used int he image. This is basically due to the fact that the DIB format underwent several extensions. Following is the DIB Header with listed fields. Each pixel in the bitmap data stores a single value used as an index into the colour palette. The colour information stored in the element at that index specifies the colour of that pixel. Availability of colour in a bitmap file varies as follow:.

Bitmap pixels are stored as bits packed in rows where the size of each row is rounded up to a multiple of 4 bytes a bit DWORD by padding. The total amount of bytes required to store the pixels of an image can not be directly calculated by just counting the bits. Since there is padding involved, the effect of round up the size of each row to a multiple of 4 bytes is required.

Padding bytes not necessarily 0 are to be appended to the end of the rows in order to bring up the length of the rows to a multiple of four bytes.