Changing Uploading Files Settings

I am about a year and a half into creating my blog and I am realizing that I really need to change the Uploading Files Settings. This seems to have been checked to sort itself into month and year based folders and this is very inconvenient for me.

I have now /unchecked/ the setting below and my assumption is that NEWLY uploaded images will now place themselves in one place (“wp-content/uploads”), is this correct?:

> [ ] Organize my uploads into month- and year-based folders

> Store uploads in this folder > Default is wp-content/uploads

Also, does anyone know if there is a good way to get the OLD images into this folder and stay linked up to the post? I have a ton of similarly named but differently sized images (apparently from clicking on the percentage sizing image option) and I want to both delete these (I can resize the originals) but I am also going to move everything into the Uploads folder. Does anyone know if this basically means that I have to go in and re-associate /each/ and every image on each and every post and/or thumbnail?

Finally, does anyone know what this setting will change and/or whether it would be helpful in what I am trying to do?:

> Full URL path to files Configuring this is optional. By default, it should be blank.

THANK YOU.