How to restore PNG files on the site?

Question

Images

Good afternoon. I don’t know all the details, maybe it happened by accident, maybe someone did it on purpose.
At the moment, there is a site where almost all PNG files are not displayed. JPG and GIF are fine. Got on FTP all the files in place and the browser uploads them successfully. But here's the problem - I tried to download these files to my computer and no program can open them (Photoshop, XnView), it says that the file is damaged or has an unknown structure.
Tried all sorts of online services - no result. Is there any way to restore them? Maybe the "encoding" got lost there, well, or some other little thing and you can fix everything in batches...
Link to the archive, inside there are several corrupted PNGs (size 21 KB) rgho.st/8GPF4CHRz

Answer 1

check what type it really is , but that's half the battle anyway,
if XNView doesn't open - draw new ones

Answer 2

and the browser downloads them successfully

that is, if you look at the site, everything is displayed, but if you download, then it's already a disaster? Or are they all already broken?

Answer 3

All broken PNGs contain the string "Adobe ImageReady". And the file header is similar to the original.
I think it's easier to restore from a backup.

Answer 4

XnView latest version does not open. There are no sources or backups, as I was told ((
Thanks to everyone for the advice, I will try .... or maybe draw again.