You can do just about anything to an image with Photoshop, but if you don't have the cash to shell out, free program the GIMP -- available for Windows, Linux, and OS X -- can take you pretty far. Here are our favourite Photoshop how-tos that also work in the GIMP.
Note: If you're looking for a more native image editor on OS X, you might want to check out Seashore. It can't do everything the GIMP can do, but it comes pretty close and runs much better on Macs.
10. Enhance And Touch Up Photos With Colour Correction And More
Retouching photos is one of the first basics of Photoshop we covered in our night school, and you have most of those tools available in the GIMP as well. You don't have the advanced histogram that Photoshop does, but you can access the colour balance, levels, and curves tools under the colours menu in the toolbar. The closest equivalent of Photoshop's "Auto Tone" feature is the white balance tool under colours > Auto, and you'll find the healing brush and clone stamp tool in GIMP's toolbox, with the familiar stamp and bandage icons near the bottom of the topmost pane.
9. Remove Red Eye
Those of us with lighter-coloured eyes always seem to look like the devil in certain pictures, and while you can remove those red eyes with a program like Picasa, you'll get much better results if you take the time to do it manually. We've talked about how to do it in Photoshop before, and the process is identical in the GIMP -- the only thing you need to know is that to change the layer's blending mode, just click the "mode" dropdown at the top of the "Layers, Channels, Paths, Undo" toolbar.
8. Whiten Teeth
Whitening teeth is easy in Photoshop, but requires a tad more work in the GIMP. the GIMP doesn't have a "sponge" tool like Photoshop, you can emulate it by creating a new layer, making saturation changes to that layer, and then using the eraser to isolate the teeth. You can find more information about this technique at this GIMP user forum thread. The GIMP does have a dodge tool, however, so you won't have to do anything differently there -- it's the last button in the top pane of the toolbox.
7. Remove Blemishes
None of us are perfect, and if you want to remove a few blemishes from your photos, it's just as easy to do in the GIMP as it is in Photoshop. Like we said above, the clone stamp and healing brush tools are right there in the GIMP, and the Resynthesizer plugin works much like the content-aware fill introduced in Photoshop CS5. With a combination of all three, you can banish that blemish and make it look as if it was never there.
6. Brighten Up A Specific Part Of An Image
Brightening up just one portion of an image is easy, no matter what editor you're using. We've already discussed the tools necessary -- mainly the levels, curves, and other colour adjustment tools -- so doing it in the GIMP is just a matter of learning the technique and knowing where the tools reside in GIMP instead of Photoshop. Check out our video tutorial to see how it's done.
5. Create Easy Reflections Of Any Image
If you want a cool reflection effect on some text or other image, it's incredibly easy to do. Our video tutorial uses Photoshop, but you can flip an image in the GIMP from the Image > Transform menu, and all your eraser options are in the toolbox, right where you'd expect them to be.
4. Extract Your Subject And Put Them On A New Background
We talked about this in our how-to on altering reality with Photoshop, and it's fairly easy to do in the GIMP as well. GIMP doesn't have a separate polygonal lasso tool, but you can still select areas in the same way with the regular lasso tool. Instead of clicking and dragging, just single-click different areas to get a polygonal selection. In fact, in the GIMP, you can even mix freehand and polygonal segments in one selection by hitting the "F" key as you select. You don't really have a background eraser either, but you can get similar effects by selecting the brush tool, setting the mode to colour erase and the foreground colour to the colour you want to erase. The magic wand tool can also get the job done if your foreground and background are different enough.
3. Fix Distorted Images
Sometimes your photos don't turn out exactly as you wanted, and to fix distortion, you can just use Photoshop's liquify tool. GIMP doesn't have a tool by that name, but you can get a very similar effect by heading to Filters > Distorts > Iwarp. You can try out other distorts as well, but Iwarp should take you wherever you need to go. Remember, it can take a little practice to get good at, so don't get discouraged with this one -- it's tough.
2. Change A Specific Color
While Photoshop has a one-click colour replacement tool, the GIMP doesn't -- but that's OK, because doing it manually will probably get you better results (besides, it builds character). Like I said above, you can just use the regular lasso as a polygonal lasso, and all the other tools in the video are available in GIMP right from the menus (as discussed above). The only thing that isn't obvious is how to change the blending mode of a layer. In the GIMP, this is right at the top of the "Layers, Channels, Paths, Undo" toolbar, under the "mode" dropdown.
1. Create Instagram-Like Effects
Unfortunately, emulating old-school Instagram-type effects in the GIMP is not as easy as in Photoshop. If you're using Photoshop, you can just download a couple of Photoshop actions, but these won't work in newer versions of the GIMP. However, doing them manually usually isn't hard -- our friends at the How-To Geek have already shown us how to make the Nashville and Lord Kelvin effects and a quick Google search should reveal details on any other effect you want.
If you're lucky, you might be able to find GIMP plugins that simulate them, too, like this Lomo plugin or this vintage plugin, though there don't seem to be as many that perfectly emulate Instagram's filters. Doing it manually might take a little longer, but it gives you more control and ultimately, a better image, so it's worth the work.
Photoshop and the GIMP aren't exactly equals, but with a bit of ingenuity, you can get pretty far with free software, no matter what you're trying to do. For more Photoshop tricks, check out our #photoshop tag, and when it comes to finding comparable tools and tricks in GIMP, remember that Google is your friend. If you're trying to do it, chances are someone else has tried before and found a solution. Got any of your own image editing tricks that work in the GIMP? Share them with us in the comments.