I thought that it would be good idea to try the embed method as I heard that there are advantages; that the images are presented better. Do I understand correctly?
A gallery embedded manually will look and function exactly the same as a gallery created with WP-Juicebox (assuming both galleries have exactly the same configuration settings).
Is there any advantage of the embed feature over the WP plugin?
Using WP-Juicebox will embed the gallery automatically (avoiding any problem which can occur when embedding manually such as file locations and pathing issues). Also, if you have multiple galleries on the same page, WP-Juicebox will load the 'juicebox.js' file only once per page (rather than once per gallery). This is recommended. (Loading the 'juicebox.js' file multiple times in a single page can cause problems, especially if the 'juicebox.js' files being loaded are different versions.)
If there are advantages in embedding, is there any step by step "recipe" for how to do this with flickr being the source of the images and with wordpress being the platform where the embed code is being used?
There are no advantages to embedding manually (but as long as the file locations and embedding code are correct, there are no disadvantages, either). However, if your WordPress site can display multiple posts containing Juicebox galleries on a single page, then there may be an issue with multiple 'juicebox.js' files being loaded. Using WP-Juicebox will avoid this potential problem.
Here are the steps required to achieve your manually embedded Flickr-sourced gallery.
(1) Create a Juicebox gallery (using Flickr as a source of images) using JuiceboxBuidler-Pro.
(2) Upload the complete gallery folder (not just the contents) to your web server.
(3) Paste the baseUrl embedding code into the body of your WordPress page (ensuring that the method of entry is 'Text' rather than 'Visual').
It does not matter where on your web server you upload your gallery folder to as long as the two paths in the embedding code (the path to the 'juicebox.js' file and the baseUrl itself, pointing towards the gallery folder) are correct.
In a WordPress site where you may have little or no control over the gallery's parent containers, I would recommend giving your gallery a fixed pixel value height (such as 600px) instead of the JuiceboxBuilder-Pro default value of 100%.
Please see this note regarding Using Percentage Heights. (Using a fixed height will avoid this potential problem.)
You mentioned that the 'juicebox.js' file should be located here: http://gateslosangeles.com/jbcore/juicebox.js But you then said "(but it is not there)" Should I simply copy that file from it's current location to the jbcore folder mentioned and delete the original file?
If you copied the entire contents of your gallery folder (but not the folder itself) to your root directory, then the 'juicebox.js' file would be in the correct location (according to your current embedding code). You could do this and you should see that your gallery displays OK.
I suspect that you may have already uploaded your gallery folder to your web server somewhere but I do not know where it might be. If you have already uploaded your gallery folder to your web server, then you can leave it exactly where it is and:
(a) Add a baseUrl line to your embedding code to point towards the gallery folder. The baseUrl an be relative (to the page containing the embedding code) or absolute.
(b) Adjust the path to the 'juicebox.js' file at the top of your embedding code (to point to the 'juicebox.js' file inside the 'jbcore' folder in your gallery folder. Again, this path can be relative (to the page containing the embedding code) or absolute.
In your (3), can you offer any instructions on how to do this, with a wordpress site?
Please see Steps #1 - #3 above.
I hope this helps to clarify things.