add_netsuite_image_through_api.php

<?php

	require_once 'PHPToolkit/NetSuiteService.php';

  	$service = new NetSuiteService();

  	$uploadFile = new File();
  	$attachFrom = '_computer'; // or $attachFrom = _web
  	
  	$path = 'imageFromComputer.jpg'; // or for image url i.e. $path = 'http://www.qspectrum.com/wp-content/uploads/2015/08/dummy-profile-pic-male.jpg';
    	$extentionType = pathinfo($path, PATHINFO_EXTENSION);
	$data = file_get_contents($path);
	$uploadFile->name = 'ImageName'.strtolower($extentionType);
	
  	if ( $attachFrom == '_computer'  ){
    		
		$base64 = 'data:image/' . $extentionType . ';base64,' . base64_encode($data);
    		$base64Image = $base64;
 
    		$uploadFile->content = $base64Image;
  	}

	$uploadFile->attachFrom = $attachFrom;

	$folderRef = new RecordRef();
	$folderRef->internalId = 19;

	$uploadFile->folder = $folderRef;
	$uploadFile->fileType = '_IMAGE';

	$uploadFile->mediaTypeName = strtoupper($extentionType).' Image';

	$request = new AddRequest();
	$request->record = $uploadFile;

	$addResponse = $service->add($request);

	if (!$addResponse->writeResponse->status->isSuccess) {
    		echo "ADD ERROR";
		echo '<pre>';
		print_r($addResponse);
	} else {
    		echo "ADD SUCCESS, internalId " . $addResponse->writeResponse->baseRef->internalId;
		echo '<pre>';
		print_r($addResponse);
	}

You can improve your if/else condtional code by extracting common piece of code from it. Overall its a good effort and helpful for newbie to use your code to save image.