Resolution affects the amount of discernible fine detail
in an image. A low resolution image looks coarse. A high resolution image looks smooth. It is like comparing burlap to silk.
Cameras are described in megapixels. This is the amount of digital information that a camera can display. More megapixels will yield finer details and give you larger and better quality photographic printouts.
There are two most common digital photography formats-TIFF (tif file extension), and JPEG (jpg).
TIFF or TIF
TIF is a good format for preserving image detail when taking photographs and editing. It is widely supported by image editing software. TIF is typically a non-compressed file format that means the files can be very large in file size. It can also use something called LZW lossless compression that can reduce the size of the image file without loss of detail information. Regrettably, not all digital cameras support this uncompressed format. TIF can be found on most higher-end digital cameras (i.e. Nikon Coolpix 4500 and 5700).
JPEG or JPG (pronounced "Jay-Peg")
The JPEG format is the king of compression. JPG is the most common format for viewing images on the Web. JPEG images are small for fast delivery over the Web and are also the most common format saved in Digital Cameras . To make files smaller to fit on small storage media, compression is used. A word of caution, don't save JPG's over and over because the images get compressed over each other and loses significant amounts of image detail and information every time it is saved. JPEG uses lossy compression with a trade offs between file size and image quality.
Avoid opening and saving a JPEG file multiple times since a JPEG file loses some quality each time. It is a bit like making a video tape copy from a copy. Every generation is of lower quality. If you will be editing an image, don't save your master or archive as JPEG. If you need to edit an image, save the intermediate image as TIFF. If you want a master copy, keep it in TIFF and you can always save a JPEG file later for email or for placing on a web page.
More information on Web Formats:
Links to other Digital Camera Resources: