How Many Pictures Will a CD Hold?

There are many ways online and offline to share digital images. Recording to a CD is one of the easiest, cheapest ways to physically share digital images, but how many images can a CD hold? There are a few factors to consider to find the answer.

CD Capacities

A limiting factor in how much a CD can hold is its maximum capacity. Currently, the market standard sizes for CDs are 650MB or 700MB for standard 12-inch CDs. There also are 8-inch CDs that hold 185MB. Some companies have developed larger size CDs; however, not all players can read these CDs.

Pixels

In addition to the maximum capacity for CDs, the image size determines how many images will fit on a CD. The larger each image is, the fewer that will fit on the CD. One of the factors that affect an image's file size is its pixels. A pixel is essentially a dot that is encoded with a specific color. The more pixels that an image has, the sharper it will be. Currently, there is a camera that can take 39MP (mega pixels) images; however, the average digital camera ranges from 1MP to 5MP. As the pixel count rises, so does the image's file size.

Compression

Because digital images can be so large, many are compressed to create smaller file sizes. There is a trade-off between how small an image can be compressed to and the quality of the picture. As an image becomes more and more compressed, the quality of the image goes down, and it often becomes "pixelated."
There is also a need to consider human perception. The human eye may not be able to detect the difference between a raw (uncompressed) file and a slightly compressed photo. According to photo.net, a 3MP image that is compressed by a factor of 10 (creating a file size that is 1/10 of the original size) is indistinguishable from the original. So why are larger MP cameras necessary?

Picture Size and MP

One factor in determining the file size of an image file is its end use. If it is going to be viewed on the computer, it may not need to be a specific size. However, if the image is going to be printed to specific sizes, it needs to have a certain resolution so it will not come out blurry. There are limits to how large a 3MP image can be printed without the image becoming blurry, which is why larger MP cameras are necessary. For instance, an image from a 5MP camera that is 8.5x11 inches will come out much clearer and sharper than one produced by a 3MP camera.

Considerations

Assuming that an image from a 3MP camera is compressed by a factor of 10, the resulting picture would be roughly 900KB, or 0.9MB. This means that an average CD with a 700MB capacity will be able to hold about 700 images. However, the specifications on each CD is not exact. Some CDs can hold a little more, some a little less. It is also possible to burn beyond the CDs specifications by overburning a disc, which is where information is burned into the buffer or lead out space of the disc. Overburning, however, can cause some or all of the information to not be readable.