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.
What size should your photos be when posting them to the web? What are the common standard digital photo image sizes? Every site I looked at had different size images, but some common themes did emerge. 240 x 160 pixels was a very common small format. Larger images were typically around 460 pixels wide.