#3517
As a new lossy image file format developed by Google specifically designed to accelerate the Web, under the condition of maintaining the same image quality, WebP format can be much smaller than JPG/JPEG format (reduce 40% or more) in size. But the problem is - WebP is not so popular that could be seen everywhere at present. As a consequence, we may have such needs for now - to convert the WebP format of images to one of the most common formats such as JPG, PNG, or vice versa.

#1911
For some webmasters or web designers, most often they need to make the webpage image smaller, in order to get a faster network transmission (faster page loading and faster image downloading) and the corresponding lower bandwidth bills.