Optimising Images for Website

[radderfire]

It's a while since I looked at best practice for optimising images for the web, and since then broadband speeds have generally improved. What are current standards for adding product images (photos) to a website and e-commerce store?

What is the maximum acceptable file size these days?

What are recommended pixel dimensions for product images?

Is it better to use .jpg or is there something to be said for .png?

Thanks

 

[radderfire]

Thanks for your thoughts.

Any more opinions guys?