I’m aware Google’s Pagespeed isn’t the best tool to use for testing site performance but I believe the results can affect Google Ranking so would like some advice on this.
I would like to fix the issue of it detecting the fact that some images are being resized by the browser. So even though I have set a thumbnail size of 690×499 in WP Show Posts and Customizer>Layout>Blog, this is still larger than they need to be when the layout is displayed on desktop or mobile.
Is the only way to get GP to generate a smaller thumbnail by going into the wordpress Media Settings and adding a thumnbnail size there?.
The problem is, this will generate a thumbnail everytime I upload a new image which may not always be required and will use up server disk space and file usage.