用PHP压缩图像

Question

I process uploaded images by php to save (after resize) by imagejpeg . As I explored, imagejpeg is the best php command to compress jpg images to reduce the file size. However, when I check my website by Google Page Speed, it says all of my images can be compressed 4-10%.

What is the common method to compress images to meet the Google standard?

Answer 1

Googles "standard" is the possible maximum to be expected by google. You need to use highly optimized image compressors that does nothing else than image compressing and therefore get a possible maximum best value here.

You can for example, open you jpeg file in a image editor like adobe photoshop and create the possible maximum best compression to be expected by you while having visual control. Highly recommended.

The GD library provides a standard conform jpeg compression which should match a library users expectation, but which might not satisfy a graphic designer (and/or google by 4-10%).