The Pros Call It "Workflow"
What happens after you take a bunch of photos with your digital camera? How you work with those image files is what professional photographers call "workflow" and you can either keep things orderly or descend into photographic chaos. If you want to be able to find your photos to enjoy later, keeping things orderly right from the start will be the better choice!
The purpose of this article is to help you work with your photos, using free software tools that you can get right now and start using right away. The tools discussed here will all have direct support for use on a computer running a recent version of Microsoft Windows, but alternative platform support will be discussed where appropriate. (For example, they also have some support for use in GNU/Linux, but not all are supported on a Mac running OS X.)
One final note before I introduce the software: The links to the pages to download the software are not affiliate links. These are real recommendations, and I get nothing from "promoting" these programs.
Picasa: Google Gives You A Hand
While I don't personally use Picasa, several of my photographer friends are always ready to sing its praises. I have experimented with it, and I think it's a very good way to get a handle on your digital photos if you're already mired in the electronic version of overflowing shoeboxes of photos. Picasa will find all of your photos and organize them for you -- what's not to like about that?! And once you can see what you're working with, you can start reorganizing them to make them easier to work with in the future. It offers other features too, such as being able to password-protect photos, remove red eye and make other fixes, write captions that will stay with the photo, make slideshows, and share photos online. It's quite a powerhouse!
For users of GNU/Linux, there's good news -- a (beta) Linux version of Picasa is now available. For Mac users, you'll need to be using a reasonably modern machine as non-Intel (PowerPC) Macs are not supported.
IrfanView: Don't Mind the Icon!
OK, so the icon for IrfanView is a bit crazy... but the software itself is very, very powerful. This is one that I used on a daily basis before I moved away from using Windows. It can handle a wide range of image modifications -- rotating, resizing, cropping, format changing, caption writing, keywording... oh, the list goes on! -- and the batch functions are incredibly helpful. Want to rename a bunch of photos and at the same time scale them to a certain size and change them from .BMP files to .JPG files? Almost easier done than said, with IrfanView. Even just for browsing photos, IrfanView is very useful. When I was a regular Windows user, it was almost always the first software I would launch after unloading photos from my cameras. It supports video files as well.
One of the very handy aspects of IrfanView is that it is built to be portable, so you can include it with a bunch of photos on a CD or USB drive, giving you an easy way to share more photos with friends and family than could reasonably be sent via email. You can even set up a CD to launch a slideshow automatically.
This software can be used in GNU/Linux — not directly, but by using it in Wine. (I think most Linux users will know what that means.) From what I can tell, IrfanView is not available for the Mac.
digiKam: Massive Feature Set
Although many might think of digiKam as a photo management tool for Linux systems using the KDE desktop, it's actually runs on all platforms that support Qt4 and KDE4, which includes Windows (Win32) and OS X. And that's good news for Windows and Mac users, because digiKam has a massive set of features that allow you to take full control of your photos. Whether you just want a local "photo album" on your computer, or you want something that will push your images out to remote systems such as Facebook, Flickr, online galleries, etc., digiKam (and the Kipi-plugins) will take care of your needs. Now that I am using Linux in place of Windows, digiKam has taken the place of IrfanView for me.
Tip for Linux users: Use the Rapid Photo Downloader for Linux to automatically move photos from your digital camera or memory cards to a digiKam-managed location on your hard disk.
GIMP: Image Editing Workhorse
One way to think of GIMP is that it is similar to Adobe Photoshop, but without the price tag. Now, some who have seen it complain about a steep learning curve, but I would say the exact same thing about Photoshop. In fact, I found GIMP to be nowhere near as difficult as Photoshop, and while Photoshop is on a CD here in my office, it's GIMP that I have installed (in Windows, Linux, and OS X).
Anyway, listing all the things you can do with GIMP would take more than one article! It goes way beyond red-eye removal, resizing, and other basic modifications, and gives you complete control over every pixel in your photos. If you're already adept enough to understand how to use Layers, for example, or you like to adjust the color balance of your photos using Curves, or a variety of other powerful tools, GIMP is ready for you. Of the programs mentioned in this article, my strongest recommendation is for GIMP.
There You Have It...
Remember, you'll get the most value from your photos if you keep them organized, and you'll find that easier to do if you build good habits right from the start. (If it's too late for that, try Picasa to get things in order.) All of the software tools mentioned above are free and provide many useful features for controlling your digital photos.