That's the one I implemented -- with a bit of low-level hackery, it could run fast enough to resize at ~5-8 fps on mobile back in 2013. But the result didn't lo

That's the one I implemented -- with a bit of low-level hackery, it could run fast enough to resize at ~5-8 fps on mobile back in 2013. But the result didn't look great on most images if you resized by more than ~15%. The technique works by calculating the "importance" field of the image once, and all the seams upfront. Then you can just number the seams from 1-n and remove the first m seams when you resize the image by m. The runtime is then O(n^2) instead of O(n^3). In contrast, with regular seam carving, you'd often update the "importance" field every time you remove a seam. The result is that the seams that get removed are less likely to introduce artifacts. I think it's a similar problem as the forward energy v.s. backward energy problem discussed elsewhere in the thread, but worse.