@fl0pp Synology NAS have different NFS and FTP paths. NFS starts in the exported directory, in your case that’s /images but the FTP path is likely /something/images
I’m not sure if this will solve your issue, but this is something you have to set on Synology NAS for them to work 100% correctly with transferring images from /dev to /images, for FTP Image Size, and for replication too probably