I am an avid Photoshop user. From blogging, graphic design, to product design sketches, I use it practically every day. But there have been times when my access to my laptop has been cut off and I was in need of some quick graphic editing software.
So this let me on a quest, to find the best replacement for Photoshop.
The search has been less then rewarding. There really isn't that many good replacements for Photoshop. For those of us who have learned Photoshop as their first tool, you can't readily sit and use another graphic program without some heavy referrals to online tutorials.
Although there are many graphic programs out there, I have chosen only 2. This is because they have the best communities with easy to find tutorials and their developers are fairly active.
The most common and widely used free alternative to Photoshop or other graphic programs. It is quite famous among our Linux brethren. It has rich functionality and tons of tutorials online. Very easy to learn and it shares many similarities with Photoshop.
Don't underestimate Paint.NET. it might have the flavor of the common Paint in Windows, but it has been developed beyond its initial scope. It has most of the common functions you would expect from Photoshop. There is also an active community of users with readily available tutorials online.