root = lxml.html.fromstring(
    """
    <div class="textbox">
        Buying this item will cost you 
        <img align="adsbottom" alt="1" src="/1.jpg;type=symbol"/>
        silver credits and
        <img align="adsbottom" alt="1" src="/1.jpg;type=symbol"/>
        golden credits
    </div>
"""
    )
pieces = root.xpath(
    '//div[@class="textbox"]/text() | //div[@class="textbox"]/img/@alt')
print(' '.join(map(str.strip, pieces)))
Python, BeautifulSoup - <div> text and <img> attributes in correct order