Example

connect_image_upload.php

<?php
function uploadItemImage($url, $access_token, $image_file) {
    $headers = ["Authorization: Bearer $access_token"];

    $ch = curl_init();

    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, ['image_data' => "@$image_file;type=image/jpeg"]);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

    $data = curl_exec($ch);
    $return_status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    print "POST to $url with status $return_status\n";

    curl_close($ch);

    return $data ? json_decode($data) : false;
}

print_r(
    uploadItemImage(
        'https://connect.squareup.com/v1/me/items/ITEM_ID/image',
        'ACCESS_TOKEN',
        'IMAGE_FILE.jpg'
    )
);
?>

I am getting Error:
stdClass Object
(
[type] => bad_request
[message] => Invalid multipart form data
)

Please help me how i can fix this issue?