The first digit assigned to all Visa cards is four, and the second through sixth numbers are connected to the financial institution. Then, either the seventh through 12th numbers, or the seventh through 15th, are the account number, while that final 13th or 16th digit is the check number.
Limited color, Lossy format, small file. GIF(Graphics Interchange Format) is limited to an 8-bit palette, or 256 colors. This makes the GIF format suitable for storing graphics with relatively few colors such as simple diagrams, shapes, logos and cartoon style images.
Reference files of lower quality than original (e.g. for web site use) - again, these files sacrifice quality for file size. Most audio files in the MPEG format (e.g. .mp3) - many varieties of the MPEG format are lossy, sacrificing quality for file size.