I noticed that using ImageMagick the images were heavier than with GD Library.
On the other hand if I also use your Image Optimizer API, the images with ImageMagic are the same size as with GD Library.
Here is an example image that I sent several times with different settings :
GD Library : 100 ko
ImageMagick : 135 ko
GD Library + Image Optimizer API : 83 ko
ImageMagick + Image Optimizer API : 83 ko
Why with ImageMagick my images have a significantly higher size if I do not use your Image Optimizer ?