Hello i'm having issue with uploading image to the cloud (Backblaze B2).

The problem is, when I use the example Thunder client to upload the file everything works fine and file is shown.

Now my problem is that when I upload with JS I don't know why it is corrupted or bugged. Like when I upload an image and download it, Windows File Manager says : file format not supported.

I decoded the file with base64 img decoder and it works fine and image is shown.

const submitForm = () => {
        var reader = new FileReader();
        reader.readAsDataURL(file);
        reader.onload = function(e) {
            // binary data
            let imagedata = reader.result.slice(reader.result.indexOf(',') + 1)

            console.log(imagedata);

            console.log(sha1(imagedata));
            const proxyurl = "https://cors-anywhere.herokuapp.com/";

            let datadf = fetch(proxyurl + 'url', {
                    method: 'POST',
                    headers: {
                        "Accept": "*/*",
                        "User-Agent": "Thunder Client (https://www.thunderclient.io)",
                        "X-Bz-File-Name": file.name,
                        "X-Bz-Content-Sha1": "do_not_verify",
                        "Authorization": "auth",
                        "Content-Type": "b2/x-auto",

                    },
                    body: imagedata,
                })
                .then((response) => {

                    return response.json();
                })
                .catch((err) => {
                    return {
                        status: 'fail',
                        message: 'API CALL ERROR',
                        error: err.message
                    };
                });
            datadf.then(res => console.log(res))
        };
        reader.onerror = function(e) {
            // error occurred
            console.log('Error : ' + e.type);
        };