Access iPhoto photos with Finder?

Question

Is there a way to use Finder to find, open, share, etc. photos in my iPhoto folder? Or is the only way to access them through the program itself?

Answer 1

Longer Answer:
iPhoto (and similar apps, like Aperture, Lightroom, Picasa) are designed to replace the Finder for anything you do with your Photos. (Like AddressBook with your addresses, iTunes with your Music etc).
Also, these apps - espcecially iPhoto and Aperture - make massive use of virtualisation in how they work, so finding files within the Library is difficult, as there is no necessary connection with how things are laid out in the iPhoto Window and how they are arranged on the Hard Drive. Accessing the files directly also any edits or metadata that you have added since import.
Anything you need to do can be done via iPhoto, and done faster and more easily too.
Want to edit with another applicaton: You can set Photoshop (or any image editor) as an external editor in iPhoto. (Preferences -> General -> Edit Photo: Choose from the Drop Down Menu.) This way, when you double click a pic to edit in iPhoto it will open automatically in Photoshop or your Image Editor, and when you save it it's sent back to iPhoto automatically. This is the only way that edits made in another application will be displayed in iPhoto.
There are many, many ways to access your files in iPhoto:   You can use any Open / Attach / Browse dialogue. On the left there's a Media heading, your pics can be accessed there. Command-Click for selecting multiple pics.
(Note the above illustration is not a Finder Window. It's the dialogue you get when you go File -> Open)
You can access the Library from the New Message Window in Mail:
There's a similar option in Outlook and many, many other apps.  If you use Apple's Mail, Entourage, AOL or Eudora you can email from within iPhoto.
If you use a Cocoa-based Browser such as Safari, you can drag the pics from the iPhoto Window to the Attach window in the browser.
If you want to access the files with iPhoto not running:
For users of 10.6 and later:  You can download a free Services component from MacOSXAutomation  which will give you access to the iPhoto Library from your Services Menu.
Using the Services Preference Pane you can even create a keyboard shortcut for it.
For Users of 10.4 and 10.5 Create a Media Browser using Automator (takes about 10 seconds) or use this free utility Karelia iMedia Browser
Other options include:
Drag and Drop: Drag a photo from the iPhoto Window to the desktop, there iPhoto will make a full-sized copy of the pic.
File -> Export: Select the files in the iPhoto Window and go File -> Export. The dialogue will give you various options, including altering the format, naming the files and changing the size. Again, producing a copy.
Show File:  a. On iPhoto 09 and earlier:  Right- (or Control-) Click on a pic and in the resulting dialogue choose 'Show File'. A Finder window will pop open with the file already selected.    3.b.
b: On iPhoto 11 and later: Select one of the affected photos in the iPhoto Window and go File -> Reveal in Finder -> Original. A Finder window will pop open with the file already selected.