Key Difference: Both Bitmap and JPG are file format for storing digital images. The term bitmap essentially means a map of bits or specifically a ‘spatially mapped array of bits’. JPG, originally JPEG stands for Joint Photographic Expert Group. JPEG is a method of lossy compression for digital photography. Bitmap, on the other had, usually refers to an uncompressed image.
Both Bitmap and JPG are file format for storing digital images. The two formats are quite similar however there are some differences to each that make some people prefer one to the other.
The term bitmap essentially means a map of bits or specifically a ‘spatially mapped array of bits’. The term bitmap is rooted in computer programming terminology. In general, raster images may be referred to as bitmaps. The file name for a bitmap image is .bmp. JPG, originally JPEG stands for Joint Photographic Expert Group. The file name for a JPEG image is .jpg or .jpeg.
JPEG is the most commonly used format for photographs. It is specifically good for color photographs or for images with many blends or gradients. However, it is not the best with sharp edges and might lead to a little blurring. This is mainly because JPEG is a method of lossy compression for digital photography.
This means that while saving the image in a JPEG format, there is a slight loss of quality due to compression. Hence, JPEG is not the greatest format in case one needs to keep making numerous edits and re-saves to the image. As with each re-save there a slight loss of quality due to compression. Still, if one only makes a few edits and the image is saved in a high quality format, the slight loss of quality due to compression is mainly negligible.
Bitmap, on the other had, usually refers to an uncompressed image. In this format, images are rendered pixel by pixel which are put together to form an image. All images work in this manner but some format compress the images together in order to garner a complete image. In this manner, some pixels are lost or looked over in preference of others. However, this is not the format in a bitmap image. A bitmap image garners each pixel individually. Hence, it is a simple format without many options available for the image, as in to apply filters or edit the images in many different ways.
An advantage to using the JPEG format is that due to compression, a JPEG image will take up a few MB of data. A bitmap image, on the other hand, is a true image and hence it renders every pixel individually. This ends up taking a lot of space. A bitmap image will take much more space than a JPEG image. Hence a BMP image in not often used on the Web. Also, as a bitmap image is a pixel by pixel image, if one tries to zoom in or enhance a bitmap picture, the image seems pixilated.
The bitmap was probably the first type of digital image format and is the basis platform for many other file types. It was also the default image format for Windows. The Paint program in Windows XP and before automatically saves the images in BMP. Hence, bitmap is generally acceptance in any and all Windows programs. However, due to the popularity of JPG, it is also accepted in most if not in all programs.
The JPEG is quite popular for web hosting of images, for amateur and average photographers, digital cameras, etc. This is mainly due to the fact that high quality images can be saved using less space.
On the other hand, lossless compression formats are popular for illustrations, drawings, text and other material that would not look good when compressed, especially with lossy compression. In illustrations and drawings, the images need to be edited and re-saved quite a number of times. The images compressed with the lossy compression will loose their clarity and crispness. This is not an issue for lossless compression formats such as BMP. However, as BMP is some simple without many options available for the image, other lossless formats such as PNG or even TIFF are preferred over bitmap.
Image Courtesy: iconarchive.com