Image:checks the property values of an image, check that

image source file is correct

Bitmap:checks an area of a web page or application after

capturing it as a bitmap

check that the web page or application is displayed as a

expected.

image chect point means check whether the charecterstic of 
the image correctly appear in web page r not.

bitmap means check whether the bitmap correctly present in 
webpage r not

For Checking whether an Image existson a webpage is "Image 
Check Point" and and Checking a part of that image 
is "Bitmap Check Point"