I have been using timthumb to generate image thumbnails on the fly for my WordPress websites. 1 of of my sites are quite big and it contains lots of images. I've noticed that it takes timthumb quite a bit of time to do its job and my site is very slow now.
To reduce my website's load time, should I generate image thumbnail everytime an image is generated and have it stored in my server (storage is not a problem for me)? Or is it still possible to generate thumbnails on the fly while keeping websites' load time minimal?
I'm implementing Amazon CloudFront to serve images for my website by the way.