Fastest way to resize image

As in the title, which is the fastest way to resize an image? I'm using Python + OpenCV 2.11 (not openCV3), and it seems cv2.resize() is very slow.

We can use CUDA with OpenCV3 (http://www.coldvision.io/2015/12/22/image-resize-with-opencv-and-cuda/), but is it supported in OpenCV 2?

Can you bulk resize images?

If you're submitting photos, or using them for a website, you'll need to be able to quickly change the pixel dimensions of those images. Luckily, a photo editing program like Adobe Photoshop can help you batch resize images for fast and accurate results.

OpenCV 2 has gpu module but unfortunately there's no bindings for Python.

CUDA programming comes with a pretty big warmup- and code complexity overhead itself.

There exists a SIMD fork of Pillow, which claims to have much better performance than ImageMagick or plain Pillow, but there are no comparisons to OpenCV. Maybe worth checking out how they compare.