Imagebuilder 25.12.4 and ipk

Is it possible to include a ipk package using imagebuilder? So far I am unsuccessful.

No.
With 25.12 we have moved to "apk" package manager and .apk files.
Opkg with .ipk has been retired.

There's Binary IPK to APK package converter, didn't test it myself.

Thanks. I have seen that as well but don't know if it can be trusted. I was not sure if there was a work around.

ipk files are simply tar.gz archives, so you can unzip and extract the contents, then install manually, if that's your thing...