Metadata is data about data!
Metadata describes a digital image file. It is similar to bibliographic data for books and articles, or food labels, map legends and data on DVDs.
Basically, it describes the Who, What, Where, Why and How of data.
Metadata can be easily manipulated so you might find different (inaccurate?) metadata the same image.
1. Right click on the image.
2. Choose View Image Info, Properties or Get Info.
This is what is shown when you right click on the Google image:
From: Wikipedia; under Fair Use
Knowing a few technical things about an image - file size, resolution, format, etc., will make it easier to work with digital images.
Resolution is a measure of sharpness in a digital picture and is usually measured by the number of pixels or dots per inch; for example, "a resolution of 1200 dots per inch"
Funny by dr_XeNo (CC BY 2.0)
File Size is the amount of space an image takes up. It is usually measured in bytes, kilobytes (1000 bytes), megabytes (1000 kilobytes), gigabytes (1000 megabytes), etc.
File Format - standardized means of storing and viewing images on computers. Each format uses a different compression scheme.