Question

I’m using ImageMagick to get 3 versions of an uploaded picture.

The problem is that the 3 new pictures aren’t optimized for web like Save For Web & Devices in Photoshop. The difference is big. ImageMagick generates files which are 5 times bigger than a web-optimized picture from Photoshop.

Can you help me to improve this issue?

This is the ImageMagick-Part:

exec($imageMagickPath." uploads/foto.jpg -resize 514x uploads/fl-foto.jpg");
exec($imageMagickPath." uploads/fl-foto.jpg -resize 320x320 uploads/hl-foto.jpg");
exec($imageMagickPath." uploads/fl-foto.jpg -resize x96 -gravity center -crop 96x96+0+0 +repage uploads/th-foto.jpg");

Of course, I want to use these 3 images on the front-end, but they are to big and slow down the entire page.

Any suggestions?

Answer 1

Imagemagick uses the parameter -quality # to set the desired quality, by which you can decrease your image-size by increasing compression. You can read more about it at their documentation. The section about jpeg says this:

For the JPEG and MPEG image formats, quality is 1 (lowest image
quality and highest compression) to 100 (best quality but least
effective compression). The default is to use the estimated quality of
your input image if it can be determined, otherwise 92. When the
quality is greater than 90, then the chroma channels are not
downsampled. Use the -sampling-factor option to specify the factors
for chroma downsampling.

In your case this would become:

exec($imageMagickPath." uploads/foto.jpg -resize 514x -quality 60 uploads/fl-foto.jpg");