Are there any other free programs like GIMP?
No.
And I'm going to stand up for GIMP here. IT IS FREE after all. The 16 bit problem is real and it does matter and Keith is right it's been a long wait but a beta of the 16 bit version is available and we should get a stable version 3.0 sometime this year.
The 16 bit problem isn't as serious as it may sound if you do your photo processing the way you should. You get the RGB conversion of your raw file done properly in the raw converter and you can then move an 8 bit TIFF to GIMP. GIMP 2.8 will open 16 bit files but it does convert them to 8 bit as it opens them.
I am not aware of any other free editor then that properly implements color management. GIMP will: a) correctly use your monitor profile. b) correctly convert a photo between color spaces. c) maintain the color space and ICC profile of photos it edits. This makes GIMP unique among free photo editors and frankly it makes
GIMP the only one that is usable. (If anyone knows of another free editor that implements a, b, and c above please let me know.) Because GIMP incorporates proper color management it can be used professionally along with a good raw converter.
Moving on, GIMP's UI isn't as elegant as Photoshop, but it's certainly usable especially in the new 2.8 interface that does away with the multiple floating windows UI. In terms of adjusting the tone response and color of a photo as well as the local tone response and color of a photo GIMP is fully capable. In addition it provides ample tools to correct shape distortion, to clone defects, to crop and re-size a photo and to sharpen a photo. It likewise has an assortment of special effects filters and assorted junk. And yes the text tool sucks.
I went looking for a photo to use as a test and found this one:
The camera blew the highlights in the JPEG -- I created the above by processing the raw file and I deliberately set up problems for GIMP to solve. I held the highlights but left the tone response poorly adjusted and deliberately screwed up the color. In GIMP I was able to:
1. Straighten the building using the Transform tools.
2. Apply a mask to hold the highlights in place while adjusting the tone response of the rest of the photo.
3. Apply a mask between layers to open up the shadows.
4. Apply a mask between layers to raise contrast in just the shadows.
5. Clone out the newspaper on the sidewalk.
6. Alter the color and tone of the blue plastic bag stuck in the fence lower left.
7. Get the white balance right.
8. Alter only the color of the sky which was too cyan.
9. Crop and size the photo.
10. Sharpen the photo which I did after converting to Lab color so as not to add color noise.
Even some commercial software out there can't compete with GIMP's capabilities. For example let's assume you have Elements. Convert a photo in Elements to Lab color and then make a tint adjustment by altering the "a" channel. I can do it in GIMP.
Here's the GIMP edit of the above photo:
Joe