I got a tech question from my Aunt today. Seems now that I've hung up my sign for my new computer business, everyone is remembering I know stuff about computers. I only hung it up yesterday!
Anyway, her question was regarding where Windows puts files, in her case pictures. Since I didn't know for sure if she was saving pictures that were emailed to her (very likely) or from her own camera, I had to hedge my bets a bit. But after I finished writing, I thought some of what I said there might help you all as well, so here's to killing extra birds with the stones I have. Really, though, I don't hate birds. Cats, sometimes, but birds are fine!
To answer your question about where files save to, and why...
What usually happens, and it does depend on where you are saving the picture from, like if you get an email and it has a picture, or if you save from your digital camera, each program has its own default place to put things. Windows itself usually will remember where you saved something to the last time, and often it will try to save the next thing there too.
If its via a web page, your web browser, like Internet Explorer or Firefox or Safari, will have its own "download" folder, too. Or your email reader program, like Outlook or Outlook Express, might have an "attachment" folder.
Ideally, Windows is expecting you to put your pictures in the "My Pictures" or "Pictures" folder, which is in your "Documents" or "My Documents" folder, depending on your version of windows. So if you can get your various programs to save there, that helps find them later!
A trick I have used in the past, if the Windows default place to save a file wasn't to my liking, I would put a shortcut to my preferred place, in the default place. That way, when Windows opened the "File Save" dialog box, I'd just double click my shortcut in that folder, and it would jump the the new folder. I may have to make a video of that so it makes sense. Its really simple, if you know how to do it!
If you can tell me your version of Windows, and names of programs, I can probably be more specific. For example, Vista has a "Users" folder on the C drive, then the User name is inside that, then there is a Pictures folder inside that, like this "C:UsersCarlinPictures" . Windows XP had "C:Documents and SettingsCarlinMy DocumentsMy Pictures" for the same thing. Hey cool, Vista finally got something easier, or at least shorter! Windows 7 is probably most like Vista in that respect, but I don't have Windows 7 yet.
Hope that helps?