DEMO
demo
PIXEL x PIXEL (FILE SIZE IN KB)

{{widget type="Magento\Catalog\Block\Product\Widget\Link" template="product/widget/link/link_block.phtml" id_path="product/4436"}}

335 X 505 (74KB)
71.76% SMALLER IN FILE SIZE

670 X 1010 (262KB)
THIS IS WHAT WE CURRENTLY USE

335 X 505 (92KB)
THIS IS 50% LESS ON PIXEL
64.88% SMALLER IN FILE SIZE
COMPARING TO THE ONE WE USE

335 X 505 (62.3KB)
76.36% SMALLER IN FILE SIZE

{{widget type="Magento\Catalog\Block\Product\Widget\Link" template="product/widget/link/link_block.phtml" id_path="product/4581"}}
168 x 254 (21KB)
TO BE USE WITH THUMBNAIL
IT ACTUALLY WILL SHRINK TO 1" X 1/2 " IN SIZE
AND IT WON'T BE BLURRY
<