Issue #2941902 by smaz: Reduce the file size for bundled images in Umami

...ontent/default_content/images/chocolate-brownie-umami.jpg

...umami_content/default_content/images/heritage-carrots.jpg

...umami_content/default_content/images/home-grown-herbs.jpg

...ent/default_content/images/mediterranean-quiche-umami.jpg

..._umami_content/default_content/images/mushrooms-umami.jpg

...ntent/default_content/images/pineapple-placeholder-10.jpg

...demo_umami_content/default_content/images/pizza-umami.jpg

...ontent/default_content/images/supermarket-savvy-umami.jpg

...content/default_content/images/thai-green-curry-umami.jpg

...ontent/default_content/images/veggie-pasta-bake-umami.jpg

..._content/default_content/images/victoria-sponge-umami.jpg

..._content/default_content/images/watercress-soup-umami.jpg