OpenCV - imread(), imwrite() increases the size of png?

Question

I wanted to try out some simple operations on files and I started with opening and saving files (I use Python)

image = cv2.imread(\"image.png\")
cv2.imwrite(         


        

Answer 1

Some png writers like GIMP write much better compressed PNGs than standard libpng, which is used by opencv. You can also open and save the image again with Imagemagick, and see what difference that makes (as compared to OpenCV).

There is even specialized software that tries to better re-compress PNGs, like pngcrush.

Can you provide the image in question? I would like to play with it, regarding file size optimization.