In computers, some pictures move and some are still; some picture files are large and some are small. Is there any secret in this? In fact, this is all related to the format of the picture. To understand this problem, you must understand the format of the picture. Common picture formats are: BMP: The standard bitmap format under Windows system. It is not compressed. This kind of image file is relatively large. The graphics we usually draw using drawing programs are in this format. JPEG (JPG): One of the most widely used image formats. This kind of image is compressed and has a smaller file size, making it easier to transmit on the Internet. Most images on the web are in this format. GIF: There are two types: static GIF and animated GIF. They are small in size. Many small animations on the Internet are in GIF format. GIF is actually an animation formed by saving multiple images into one image file. PSD: A special image format for the image processing software Photoshop, with larger image files. PCX: A format developed by ZSOFT when developing the image processing software Paintbrush. It is a compressed format that takes up less disk space and offers the advantages of compression and full color. PNG: Similar to the JPG format, many images on web pages are in this format and support image transparency.