Q: I attempted to transfer photos from my computer to a cd disc to reduce what is on my computer and in the cloud and have more space. What is the way to do this without losing anything?

to reduce what is on my computer and in the cloud

How big is your iMac's hard drive and how much free space do you have on it?  What do you mean by space in the cloud?  What cloud feature are you referring to?

CDs and DVD discs are not a good way to backup files.  Copying image files to a CD is not going to save enough room to make a dent in the storage space.  CDs only store about 700 MBs.  You would need many CDs to make a difference and then you'd have a difficult time locating an image on one of them.

A much better solution IMO would be to get an external HD, formatted OS X Extended (journaled) with Ownership set to be ignored

and move your entire library to it and run from there. You can also use it to store other documents that you don't need on your boot drive.  Of course you would need a second EHD to backup both of the other HDs for protection with Time Machine or the backup application of your choice.