Map mydisk.img as /dev/loop0 and use gparted to resize:
udisksctl loop-setup -f mydisk.img gparted /dev/loop0 udisksctl loop-delete --block-device /dev/loop0
udisksctl is part of the udisks2 package.
Map mydisk.img as /dev/loop0 and use gparted to resize:
udisksctl loop-setup -f mydisk.img gparted /dev/loop0 udisksctl loop-delete --block-device /dev/loop0
udisksctl is part of the udisks2 package.