<?php
require "vendor/autoload.php";
use Google\Ads\GoogleAds\V10\Resources\CampaignAsset;
use Google\Ads\GoogleAds\V10\Resources\AdGroupAsset;
use Google\Ads\GoogleAds\V10\Services\CampaignAssetOperation;
use Google\Ads\GoogleAds\V10\Services\AdGroupAssetOperation;
$googleAdsClient = new GoogleClient();
$customerId = "123456789";
$adGroupId = "123456789";
$assetResourceName = "example/1234/example/1234";
$imageExtensionAdGroupAssetOperations = [
new AdGroupAssetOperation(['create' => new AdGroupAsset([
'asset' => $assetResourceName,
'ad_group' => ResourceNames::forAdGroup($customerId, $adGroupId),
'field_type' => AssetFieldType::MARKETING_IMAGE // also tried with AssetFieldType::SQUARE_MARKETING_IMAGE
])])
];
$adGroupAssetServiceClient = $googleAdsClient->getAdGroupAssetServiceClient();
$response = $adGroupAssetServiceClient->mutateAdGroupAssets(
$customerId,
$imageExtensionAdGroupAssetOperations
);