Comment on SEO Recent Posts WordPress Widget by SEO Dave.
“Tools” >> “Stallion Regenerate Thumbnails”
Go to “Stallion Theme” >> “Performance Options” : “Regenerate Image Thumbnails Admin” and turn the feature on “Regenerate Tool ON**”.
Once the feature is on you can regenerate your WordPress images and if you have a plugin like EWWW Image Optimizer Plugin active the regenerate images will be better optimized which will improve performance.
You’ll also have all the Stallion image sizes as well like the 500px wide image which should be your maximum image size loaded on a webpage: anything wider than 500px will trip a Google PageSpeed Insights Tool Mobile Image Optimization warning: relatively new Google mobile page speed metric warning.