Getting image to load with or before Javascript

Hi there,

I have a very specific question I hope has a simple answer. My client wants the website to be even faster. The recommendation from a colleague is below:

Is there a way to get that first main picture to load with or before the JavaScript? This makes the site seem slower and if that loaded first and everything else after, it would look really quick.

Please let me know if this is possible and any assistance would be greatly appreciated.

Deanna