for k in d['set']['item']:
    dd = '{url}{ext}{end}'.format(url=imgurg, ext=k['i']['n'], end='?id=Y6YPH3?&wid=1280&hei=877&fmt.png')
    t = requests.get(dd)
    out = open('images/%s' % dd.split('/')[-1], 'wb') #сохранение картинки
    out.write(t.content)
    out.close()
    footlocker.append(('img', dd.split('/')[-1])) #запись в словарь

ad = requests.get('http://www.footlocker.com/product/model:132512/sku:A1781919/timberland-roll-top-mens/tan/tan/').text #сылка для примера

 bb = re.findall(r'AVAILABLE_SIZES:[" "]', ad)
 print(bb)

 out:
[]
[]
[]
[]
[]
[]
[]