title: put a placeholder image until relevant image is loaded
body: <p>I am working on a rails app. The search page shows all listings with images fetched from amazon s3. The issue am facing now is that my layout getting messy until all the image is loaded fully. So i put a placeholder image and now the issue is that how to replace it when the actual image is loaded from s3..How can we know the image is fully loaded and change the image accordingly?  Thank you in advance!</p>