I am not sure where I put all my notes on imagemagick and the tool convert included in image magick.
Here is one a cool image compression: convert -strip -interlace Plane -gaussian-blur 0.05 -quality 85% source.jpg result.jpg
To make google speed happy: convert -strip -interlace Plane -gaussian-blur 0.05 -quality 65 -interlace JPEG -sampling-factor 4:2:0 -colorspace sRGB The-Garden-600px.jpg The-Garden-600px.jpg
Or this: -sampling-factor 4:2:0 -strip -quality 85 -interlace JPEG -colorspace sRGB