TIFF and JPEG

What are TIFF images? If Quality is higher why are images usually JPEGS?

 

Because jpegs are around 5-6 times smaller than TIFFs, making it easier to store them, although there may be a very slight deterioration in quality.

 

For an explanation on the various image formats, look here:

http://en.wikipedia.org/wiki/Image_file_formats

As Steeev says, for general usage without too much editing , jpeg is okay.

 

Jpeg is an image format that is based on integer Fourier transformation as well as algorithms that correctly decrease colors amount. It is well designed for multicolor images compression such as photos.
Tiff uses the compression without losses and is based on the search of specific picture elements that is accordingly very convenient for not colored plots, graphs, diagrams

TIFF is a lossless file format. TIFF can store grayscale, RGB color, false color, floating point and binary images. The other one is meant for storing color images - JPEG for RGB.
JPEG is good for photographs and shaded colors.

also see here:
http://www.scss.com.au/family/andrew/camera/jpgvtiff/