CBZ/CB7 to ePub image renaming, why?

[Uhuru N'Uru]

I have tried this so many ways, and nothing seems to stop what should be a simple switch.

CBZ, can't get the cover (1st file) to automatically show up in Metadata.

CB7 has no such issue, so I selected that as the source format.
That gets imported to Calibre with filenames unchanged.

Images are just JPG, Large, but under 3000 Pixels width/height, and some panels are landscape, others portrait, and no matter what name I use, when creating the CB7 file ePub, insists on renaming the files, for no good reason.

My sample CB7 is the largest file number with 156 images, numbered sequentially 0 to 155, with 0 being the cover image.
I would prefer if this could be set as cover image without renaming from 0, to cover but that's not my main issue, it's the renaming of the content images.

Where n = 1 to 155 with increment n = n+1

Calibre conversion to ePub has given two outputs
n - n
Which was a PNG, but when I found the setting to force it to JPG, I got
n_0

How can I stop Calibre from constantly changing my already very basic filenames, for no valid reason.
In the worst case attempts, the original files were retained, but Calibre still created renamed duplicates, and used those ones instead.

At least I'm only getting one file now, but how hard can it be, to use the existing images, unaltered in any way.

I just want the name, content and filesize to be identical to my CB7 sources.