Look at picture format

These are types of picture format used in digital camera:
JPEG
Lossy This file format is the most common. It’s universally recognized. You can select the amount of compression and subsequent quality or loss of quality in the camera or in the computer.

TIFF
Lossless TIFF is a standard photo or digital publishing format. It can be somewhat compressed but in order to lose no quality, the amount of compression is limited. This is a good finished file format and retains high image quality. You can select to shoot TIFF photos with many cameras.

CCD RAW
Lossless You can set the more expensive prosumer and professionalcameras to save the data directly from the CCD chip in the camera. This saves a huge amount of image information and is used by professional photographers and graphic artists to gain maximum image quality and flexibility. It’s a very large file and severely limits the number of images that can be stored on common memory cards.

When a lossless compression image is uncompressed, its quality matches the original source. Lossy compression degrades images to some degree, and more compression equals more image loss. Use the least compression you can for the original image. You can always compress it more with editing software.