Deployment on gh-pages error

Hello. I am a new self taught developer and I have created my portfolio using create-react-up and i uploaded it on gh-pages but something is wrong. When i open the url of my published website the landing page and the about page does not render at all. They render like there is an opacity: 0.2. And the projects page renders with a small delay. I tried to compress the pictures as much as i could but it did not work except from projects page(which still has some delay).Here is the repo:

And here is the live demo:

And in addition to the problem i already have there is an issue when i refresh the page i get an error of 404 page nor found. If anyone could help i would be grateful. Thank you in advance and sorry if my question is not well formatted… I hope i will be better some day!