Delete unwanted disk images

[calliex]

I wanted to wipe an old iMac we had at work to start fresh. I had a bootable flash drive with sierra on it so I booted from it.
I went into disk utility to wipe the drive and found two OS disk images along with internal drive. I tried a couple things to remove the disk image with no luck. I was able to wipe the main disk and installed sierra. I would like find out why I could not remove the disk images.

 

[chrfr]

I wanted to wipe an old iMac we had at work to start fresh. I had a bootable flash drive with sierra on it so I booted from it.
I went into disk utility to wipe the drive and found two OS disk images along with internal drive. I tried a couple things to remove the disk image with no luck. I was able to wipe the main disk and installed sierra. I would like find out why I could not remove the disk images.

Are you sure the disk images were not the installer the computer was using to boot? If you erased the internal drive, there were no disk images left on it.

 

[calliex]

I booted from a thumb drive and then brought up disk utility.
It listed the main drive partitions and below that two disk images that look like partitions someone used to install OS
I was allowed to erase the main drive partitions but was not allowed to do anything with the disk images. I just wanted start fresh. I am using the iMac fine just wanted to recover those disk images.

 

[chrfr]

I booted from a thumb drive and then brought up disk utility.
It listed the main drive partitions and below that two disk images that look like partitions someone used to install OS
I was allowed to erase the main drive partitions but was not allowed to do anything with the disk images. I just wanted start fresh. I am using the iMac fine just wanted to recover those disk images.

Those disk images are the USB installer.

 

[calliex]

Really, so if I bring disk utility on the iMac I should not see them, right.

 

[chrfr]

Really, so if I bring disk utility on the iMac I should not see them, right.

Right. If you think about it, the Mac has to be booted from some disk when you start from the USB drive, and that has to be represented by something in Disk Utility.