Output PNG base64 when decode image path is -

[Thearas]

So we can get data url quickly:

local hash=$(thumbhash encode "$img" | awk -F ': ' '{print $NF}' | xargs thumbhash decode - | awk -F ': ' '{print $NF}')
echo "data:image/png;base64,$hash"

[Thearas]

PTAL @Astropilot