IT PROBLEMS

The BMP file format, sometimes called bitmap or DIB file format (for device-independent bitmap), is an image file format used to store bitmap digital images

就是將影像以每點的方式記錄下來的格式

http://en.wikipedia.org/wiki/BMP_file_format

In computing, JPEG is a commonly used method of compression for photographic images. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality

這是一個就壓縮的檔案格式, 這壓縮方式是有損失的, 即是不能完全回復本身的影像

http://en.wikipedia.org/wiki/JPEG_file_format

Graphics Interchange Format (GIF) is a bitmap image format that was e format supports up to 8 bits per pixel, allowing a single image to reference a palette of up to 256 distinct colors chosen from the 24-bit RGB color space. It also supports animations and allows a separate palette of 256 colors for each frame.

GIF 只以256色來表達, 所以如果是一張真實的相片用 GIF 的格式來儲存, 顏色方面可能會有損失, 而失真, 或層次感

http://en.wikipedia.org/wiki/Graphics_Interchange_Format

Portable Network Graphics (PNG) is a bitmapped image format that employs lossless data compression. PNG was created to improve upon and replace GIF (Graphics Interchange Format) as an image-file format not requiring a patent license.

PNG 是取代 GIF 的格式, 有 24-bit 的顏色, 基本上可表達絕大部份可見色

http://en.wikipedia.org/wiki/PNG_file_format

Tagged Image File Format (abbreviated TIFF) is a file format for storing images, including photographs and line art.

http://en.wikipedia.org/wiki/Tagged_Image_File_Format