Ventoy not booting .img files

[Reedemer0fSouls]

I make partition images in Ubuntu KK. If I save these images as .iso, Ventoy boots them just fine, however, if I save them as .img, Ventoy refuses to boot them. What am I doing wrong? I though Ventoy was supposed to boot .img files, was it not?

[longpanda]

There is a standard specification for bootable ISO files, but not for .img files.
Different .img files have different format/layout, so Ventoy can boot normal .ISO files, but Ventoy can only boot some .img files, not all.
Ventoy need to test and adapt for each type of .img files.

[Reedemer0fSouls]

There is a standard specification for bootable ISO files, but not for .img files.
Different .img files have different format/layout, so Ventoy can boot normal .ISO files, but Ventoy can only boot some .img files, not all.
Ventoy need to test and adapt for each type of .img files.

Many thanks! That clears it! From now on, I'll make sure I save them as ISOs.

[timboxy]

I have tried saving bootable USB's as .img files using both dd and "Gnome Disk" (they produce the same result) by they don't boot. I have tried both the bootable partition and the whole device eg. /dev/sda1 and /dev/sda.

Changing the file extension to .iso doesn't fix the issue. Is there a recommended way of creating an ISO variant?