Masonry thumbnail image browser-side resizing issue

Hi Enflod team,

We are using Masonry to display an index of blog posts on various pages. For each post we also define a thumbnail picture which is usually one of the (non-resized) pictures used on the post itself. Doing this we get a lot of warning messages and penalty score on various website-checking sites like GT Metrix or Pagespeed Insights that these thumbnail pictures are being resized on the browser side and that this should be avoided. We tried to solve this by defining resized pictures which have exactly the required width on deskto as thumbnail. This has helped to turn off the warnings and massivly improve the score. But this causes the images being not responsive on the mobile devices and thus isn’t really a solution.

Guess that there should be an easy solution here which you would hopefully would be able to tell.

Best regards
liapos