Some File Extensions Can Confuse Google Search

Technically, when it comes to using file extensions in your URLs, it doesn't really make a difference which one you use for ranking purposes. .PHP, .HTML, .ASP, etc - it doesn't matter. But if you use image based file extensions for web page based file extensions, that might end up confusing Google Search for a period of time.

from Search Engine Roundtable https://ift.tt/36WwP9W