I have a jpg image.
I need to know "overall average" the color of the image. At first glance there can use the histogram of the image (channel RGB).
At work I use mostly JavaScript and PHP (a little Python) therefore welcomed the decision in these languages. Maybe ther are library for working with images that address similar problems.
I do not need to dynamically determine the color of the picture. I need just once go through the entire array of images and determine the color of each separately (this information I will remember for future use).
A shorter solution for true color image would be to scale it down to 1x1 pixel size and sample the color at that pixel:
$scaled = imagescale($img, 1, 1, IMG_BICUBIC);
$meanColor = imagecolorat($img, 0, 0);
...but I haven't tested this myself.
Detect "overall average" color of the picture