content.js

const postContainer = document.querySelector('.scaffold-finite-scroll__content');
const all_posts = [];

let src={
    link:null
}

chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
      src.link=message.message;
      updateProfilePic(all_posts,src);
      sendResponse({ response: "Hi there from content.js!" });
});
  


postContainer.childNodes.forEach(e => {
    if (e.nodeName === 'DIV') {
        all_posts.push(e);
    }
})

updateProfilePic(all_posts,src);

const mutationObserver = new MutationObserver(entries => {
    const posts = [];
    entries.forEach(entry => {
        if (entry.addedNodes[0] && entry.addedNodes[0].nodeName === 'DIV') {
            posts.push(entry.addedNodes[0]);
            all_posts.push(entry.addedNodes[0]);
        }
    })
    updateProfilePic(posts,src);
})

mutationObserver.observe(postContainer, { childList: true, subtree: true });


function updateProfilePic(posts,src) {
    posts.forEach(post => {
        const actorComponent = post.querySelector('.update-components-actor');
        console.log(actorComponent);
        if (actorComponent) {
            const imgWrappers = actorComponent.querySelectorAll('.ivm-view-attr__img-wrapper');
            
            imgWrappers.forEach(imgWrapper=>{
                    if(imgWrapper.children[0] && imgWrapper.children[0].src && src.link){
                        imgWrapper.children[0].src=src.link;
                        imgWrapper.children[0].style.objectFit="cover";
                    }
            })
        }
    })
}