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.
File size refers to how big the file is measured in kilobytes (KB) or mega bytes (MB) Eg 4.0 mega-pixel digital camera image - approx 1 Mb (1000 KB) The bigger the file size the longer it will take to download on a web page. Wrong file type affects image quality and file size. Photos should be JPEG (.jpg) file type, and simple line art with few colours should be GIF (.gif) file type.