just a question about macrostock.

photos that you send to macrostock agencies (like Alamy) must have exclusivity? or you also sell them as a prints? or maybe on microstock site il lower resolution?

They don't even need to be exclusive if they are set up as rights managed.

There is a rights managed license and a rights protected license.  Under the rights managed license, the presumption is that you know where the images have been licensed before so that if the customer wants them on an exclusive basis, you can tell them where in the world they can use them exclusively. 

On a rights protected basis, the presumption is the image is exclusive to Alamy and they can manage the rights for you.