If its your own web server and its deleted from that, it will still "most likely" be cached somewhere on the internet (another webserver) so in theory it can be recovered, it would just be a needle in a haystack
I.e., if I were to post a picture on here. Somebody somewhere would save it. And then I deleted it...but the person that saved it will still have it, and could upload it again to another place...and more people could save it.
Just like all the Tweets you see famous people / politicians / etc. post - one person gets a screenshot before it being deleted and then re-shares it...and it's done.