Unable to correctly SYNCH "Gallery" & "Photos" on my Galaxy S5, Samsung DUOS, and Google+

[fourcand]

Unable to correctly SYNCH "Gallery" & "Photos" on my Galaxy S5, Samsung DUOS, and Google+

I own a Galaxy S5 and a Samsung Galaxy S Duos 2 - S7582 DUAL, which I used for my international travelings. I also have a Macbook Pro that I usually used to access my Google+, and that is my preferred platform used to manage my photos, specially to delete unwanted pictures.
Just to make matter a bit more compacted, I also have Picasa installed on my MacbookPro, where I happened to have a lot of old pictures dating way back.
I noticed, however, that my photos are NOT properly synched between my devices and the usage of Google+ on my laptop.
For example, if I delete pictures, say on my galaxy S5, the photos are not deleted on my laptop Google+ and/or my Samsung S Duos 2.

I also noticed that I am unable to do multiple deletion of my photos from the "Photos" app. I can ONLY delete multiple pictures/photos ONLY from "Gallery". I am unable to do MULTIPLE delete of photos on my "Photos" app. Is this correct? Am I doing wrong, if any?

Thanks,
Robert