Aşağıdaki kodla sadece resim linkini çekebilirsiniz. Srcsetler'de çekilsin isterseniz paterni sadece (https?://.*.(?ng|jpg)) bu olarak bırakırsınız.

import re

text = '<li class="ez-toc-page-1 ez-toc-heading-level-2"><a class="ez-toc-link ez-toc-heading-1" href="https://www.diyncrafts.com/12126/home/gardening/100-expert-gardening-tips-ideas-and-projects-that-every-gardener-should-know/#Make_a_drip_feeder_using_an_old_soda_bottle" title="Make a drip feeder using an old soda bottle.">Make a drip feeder using an old soda bottle.</a></li><li class="ez-toc-page-1 ez-toc-heading-level-2"><a class="ez-toc-link ez-toc-heading-2" href="https://www.diyncrafts.com/12126/home/gardening/100-expert-gardening-tips-ideas-and-projects-that-every-gardener-should-know/#Pot-in-a-pot" title="Pot-in-a-pot.">Pot-in-a-pot.</a></li><img class="aligncenter wp-image-12128 size-full" src="https://cdn.diyncrafts.com/wp-content/uploads/2015/05/2-soda-bottle-dip-feeder.jpg" alt="Make a drip feeder using an old soda bottle." width="499" height="604" data-wp-pid="12128" srcset="https://cdn.diyncrafts.com/wp-content/uploads/2015/05/2-soda-bottle-dip-feeder.jpg 499w, https://cdn.diyncrafts.com/wp-content/uploads/2015/05/2-soda-bottle-dip-feeder-248x300.jpg 248w" sizes="(max-width: 499px) 100vw, 499px" />'

imageLink = x = re.findall('src="(https?:\/\/.*\.(?:png|jpg))"', text)

print(imageLink[0])