Filezilla issue

Hey everyone, I'm cloning my old pc to my new one using filezilla. The source (my old PC) has 500gb storage capacity, but only 340gb are used. I created a disk image of that system onto an external harddrive with 500gb capacity. The target/destination (my new pc) has a storage capacity of 480gb. When I want to write the disk image to the new pc filezilla says that the destination disk is too small. What do I need to do? Do I only need to shrink the partition of the external drive or do I have to shrink the actual system partition on my old pc before creating a disk image from it?

Any help is greatly appreciated