title: How to optimize external images on rails app
body: <p>I have a successful rails app which is on the market. </p>
  
  <p>The app fetches external images served by different Dealer management systems and showcases the images directly. However, running the speed tests shows that images itself are the culprits. They are taking 4+ MBs and is lowering the speed of the app. Especially for mobile phone browsers (40-50% of our customers use mobile phones), it has to be optimized. </p>
  
  <p>My question is if I only want to showcase thumbnails, how can I use external images and showcase them on my website after optimizations ? </p>
  
  <p>Using carrier wave and paperclip for our own uploaded image is fine and works great but is there any on the fly optimizations used in the industry for external images?</p>