It likely did, its just the filesystem inside the VM didn’t detect and resize on first boot.
LXD does not have control of the filesystems inside a VM so cannot resize them itself (unlike containers).
This is how to resize the root disk inside an Alpine VM:
lxc init images:alpine/3.16 v1 --vm -c security.secureboot=false
lxc config device override v1 root size=50GiB
lxc start v1
lxc shell v1
v1:~# df -h # root partition /dev/sda2 is too small.
Filesystem Size Used Available Use% Mounted on
devtmpfs 10.0M 0 10.0M 0% /dev
shm 490.3M 0 490.3M 0% /dev/shm
/dev/sda2 3.7G 177.2M 3.5G 5% /
tmpfs 196.1M 260.0K 195.9M 0% /run
/dev/sda1 98.4M 266.0K 98.2M 0% /boot/efi
config 231.5G 38.8G 180.9G 18% /run/lxd_config/drive
Lets resize it:
v1:~# growpart /dev/sda 2
CHANGED: partition=2 start=206848 old: size=8181727 end=8388574 new: size=104650719 end=104857566
v1:~# resize2fs /dev/sda2
resize2fs 1.46.5 (30-Dec-2021)
Filesystem at /dev/sda2 is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 7
The filesystem on /dev/sda2 is now 13081339 (4k) blocks long.
v1:~# df -h # Now root /dev/sda2 is correct size.
Filesystem Size Used Available Use% Mounted on
devtmpfs 10.0M 0 10.0M 0% /dev
shm 490.3M 0 490.3M 0% /dev/shm
/dev/sda2 48.3G 182.7M 48.1G 0% /
tmpfs 196.1M 260.0K 195.9M 0% /run
/dev/sda1 98.4M 266.0K 98.2M 0% /boot/efi
config 231.5G 38.8G 180.9G 18% /run/lxd_config/drive
This is similar to How can I expand the size of VM - #4 by tomp