Macrium Reflect- leaving junk?

I am not aware of any junk or spyware left by Macrium. If you have imaged the disk with Macrium installed on it then by definition a restore of that disk will also restore Macrium. If it is not the disk with Macrium installed on it then no it will not install itself and if this restore is to a machine that does not already have Macrium installed you would have to download and install it on the new machine if you wanted to.

No problem. It connects to the internet to look for updates.

It is not a good idea to create an image on the same disk that you are imaging because if the disk fails you will not be able to restore from it. With Macrium you just point the output to any folder on your external drive you like and it will create a file there that contains the image. If you are imaging your system disk with Windows on it you will need to create a recovery DVD which you can boot from to do a restore because you can't restore an image over a running Windows system for obvious reasons.

No because you will overwrite the image you are trying to restore from.

t is not a good idea to create an image on the same disk that you are imaging

I agree with kado. Currently I use Macrium and Easus ToDo image backups. Before either of those I bought Paragon. Every time I tried that "backup capsule" scheme in Vista or later I had problems with my partition table. In fact, what fixed it was I did the Macrium trial. When I restored to test it, it asked if I wanted to copy the MBR from backup. I clicked Yes. My partition table was fixed.

NTFS Vista and later is slightly different than NTFS on XP. I gave up waiting for Paragon to get it right. Even if it did work, many nasty malwares know how to scotch your system so it won't boot. The backup capsule is a convenience if yoiu do frequent tests and restores. It's not good for malware or disk failure recovery.

But now with eSata and USB 3.0 docking stations, the restore from an external drive can be as fast or faster. Reading from the backup capsule then writing to the partition being restored thrashes the disk in most cases. A read from a USB 3.0 drive in a docking station can be much faster. There's no real need for the backup capsule. (Of course now with the price bubble buying internal drives to stick in docking stations is not as economical as a few months ago. But if you have the drives already you are golden.)