Custom preloader ends before the images finish loading

Hello, I have a question concerning Custom preloader (the loading animation before the website opens. )

I’ve made an custom preloader by refering to the webflow video page.
https://www.youtube.com/watch?v=VthMa3jXjJ4

When I open the completed website, the loading animation appears first but ends quickly before the images still loading inside the website.

I’d like to load the images first and then end the preloader so that all the words and images are ready to show on the website.

It’s seems funny when the website opens before the images are not shown.

I’ll paste the website URL that I’ve made.
https://kazukis-ukiyoe-website.webflow.io/

Does anybody know how to load properly??