Optimizing your images is one of the quickest ways to fix a sluggish site....

https://station-wiki.win/index.php/How_to_Properly_Resize_Images_for_Faster_Page_Load_Time:_An_Editor%E2%80%99s_Guide

Optimizing your images is one of the quickest ways to fix a sluggish site. Start by renaming your files to be descriptive and writing helpful, relevant alt text for accessibility