Is there a way to sync OS X Photos app with Android Phone?
Here is how you can sync from Dropbox (or a directory of your choosing) into Photos, when new photos are added:


Open Automator, and create a "Folder Action"

On the top where it says "Folder Action receives files and folders added to" select "Choose folder", then "Other", and select your Dropbox folder (or whichever directory contains your photos)
Add a single Run AppleScript action with the following code:

on run {input, parameters}
    set file_strings to {}
    repeat with current_file in input
        set file_as_string to (current_file as string)
        if words -2 through -1 of (do shell script "file --mime-type " &amp; quoted form of (POSIX path of file file_as_string as string)) contains "image" then
            set file_strings to file_strings &amp; {(file_as_string) as alias}
        end if
    end repeat

    tell application "Photos" to import file_strings
end run


Your Folder Action should look like this:

Now save it with a name of your choosing, and from now on, photos added to the folder you chose will be imported to Photos.


Let me know if anything goes wrong!