I need to replace all url in string...

Hi,

I need to replace in javascript regex, all url in string outside any html tags and which include the domain "steemitimages.com".

I have this string:

http://google.com/ and a sister which is also a kitten 
http://s3.amazonaws.com/rapgenius/filepicker%2FvCleswcKTpuRXKptjOPo_kitten.jpg  
http://s3.amazonaws.com/rapgenius/filepicker%2FvCleswcKTpuRXKptjOPo_kitten.jpg
http://s3.amazonaws.com/rapgenius/filepicker%2FvCleswcKTpuRXKptjOPo_kitten.jpg https://steemitimages.com/0x0/https://steemitimages.com/0x0/https://gateway.ipfs.io/ipfs/QmWqwTSacujoQ9ZCSsLmDjo3ER61oZpe9jeCGRsyXbu11S

and i need to to get only the links from https://steemitimages.com/0x0 if the url reside outside a img tag.

I want to replace al url strings from this to img tag if this are not ready in one.

can help me?

Thank you