I examined the following file:
https://tarballs.opendev.org/openstack/trove/images/trove-master-mysql-ubuntu-xenial.qcow2 (~ 800MB)
It's compressed, but I found that 7Zip could extract the files from the image.
If PhotoRec can recover your file contents, then your image is not compressed. Try the free version of DMDE, or perhaps you could try 7Zip.
Header:
Code:
Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
00000000 51 46 49 FB 00 00 00 03 00 00 00 00 00 00 00 00 QFIû............
00000010 00 00 00 00 00 00 00 10 00 00 00 01 00 00 00 00 ................
00000020 00 00 00 00 00 00 00 08 00 00 00 00 00 03 00 00 ................
00000030 00 00 00 00 00 01 00 00 00 00 00 01 00 00 00 00 ................
00000040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000060 00 00 00 04 00 00 00 68 68 03 F8 57 00 00 00 90 .......hh.øW....
00000070 00 00 64 69 72 74 79 20 62 69 74 00 00 00 00 00 ..dirty bit.....
00000080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
000000A0 00 01 63 6F 72 72 75 70 74 20 62 69 74 00 00 00 ..corrupt bit...
000000B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
000000C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
000000D0 01 00 6C 61 7A 79 20 72 65 66 63 6F 75 6E 74 73 ..lazy refcounts
000000E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................