Torvalds dismisses photo editing as a task for "professional photographers", but our amateur cameras are taking phenomenally detailed pictures, and even making fairly simple edits is a compute-intensive task. He may be right, but he may equally be wrong.
Torvalds is being completely ridiculous here. Avid used to be the domain of professional film editors but iMovie is incredibly popular. We even see cell phones these days sporting 4k cameras. My Lumia has a 41 megapixel sensor! I have a RED camera and it's "only" 18 megapixels. In fact the less professional you are the more processing power you need. Photoshop's paint brush can accomplish wonders in the hands of a professional touch-up artist. But Photoshop's Content-Aware-Fill is processor murder and designed specifically to intelligently replace a professional artist. Take something like 3D rendering. You could have someone hand paint every frame. It would without question require a professional artist. But if you want a pretty picture at the push of a button you want raytracing.
This is actually something that you see happening today in the high-end VFX market. It used to be that raytracing was too compute intensive for films. But for amateurs and non-artists ironically enough ray tracing was fine. The architect only needed to render 3 frames. Waiting a day was perfectly acceptable there wasn't another 100,000 frames that also needed to get rendered. In film there wasn't time for something like Global Illumination and the shortcuts caused unacceptable flickering. Now the film industry is starting to embrace advanced lighting like GI and they're getting all of the bounces and detail that used to take hundreds of lights to fake automatically. It's making artists more productive but it's coming at the cost of increased compute time. Again a professional lighter can as an artist fake global illumination. An amateur could simply position the sun, turn on GI and wait 18 hours.
The future will be an Automagical button that not only fixes your photo *cough* instagram *cough* but also performs even more advanced editing like "Remove the gray clouds and put in a photorealistic blue sky. Oh yeah, and also change the lighting of the photo to make it look sunny!" That's going to be far more CPU intensive than any photoshop filter currently in existence and it'll be targeted as much as your average cell phone user as a professional.