Hurry to prevent long page load times for pages containing images, it is best to use a compressed file format such as jpg, as well as appropriate image dimensions and
resolution.
magnification.
orientation.
colors.

To prevent long page load times for pages containing images, it is best to use a compressed file format such as JPG, as well as appropriate image dimensions and  resolution.

Explanation:

Resolution is a term used in computer science and in digital image processing to describe the number of pixels used on, for example, a screen. The higher that number, the higher the maximum resolution of the screen.  

Resolution is actually the resolution of an optical device. Advances in technology made it possible to improve the resolution. The result was that on a surface that remained the same size, more optically active elements (pixels) could be realized. When the resolution of a screen is increased, more pixels can be displayed on that screen.