What is the difference between firmware recovery's img and the firmware zip file from the download page?

Hi, does anyone know the relation between 1) these img files from Firmware Recovery - QNAPedia and 2) the OS images from Download Center | QNAP?
In particular, is there a way to bypass 1) the “firmware recovery” and directly skip to 2) Download Center | QNAP?

My motivation for asking the question is based on https://community.qnap.com/t/cant-reach-ts-1253u-rp and https://community.qnap.com/t/overriding-the-firmware-update-check-cross-upgrade . The img provided at https://download.qnap.com/Storage/tsd/fullimage/F_TS-X53U_20141125-1.2.8.img is missing a few files, but I am unable to get support or the escalation team to help with a working image. So if I can bypass that first step, or if someone has a working image for a TS-1253U-RP, that would really help.

Thanks!

Given the complexity of your situation, and as we’ve confirmed a support ticket has already been opened for your case, our Support team will continue to assist you directly in resolving your issue.

Thank you for your patience and cooperation!