Determine if image is Grayscale or Color using JavaScript?

Question

Is it possible to determine if a given image is grayscale or color using JavaScript?

Answer 1

Take a look at http://www.pixastic.com/lib/docs/actions/colorhistogram/

This will easily provide the data you need to determine this.

Answer 2

1. draw image to canvas

2. loop through image data

3. test for each pixel if red-cahnnel == green-channel == blue-channel (all color-channels have the same value)

if true for all pixels it is grayscale, if you hit the first pixel that does not meat the condition you can stop and it is color.