as you can see the cached image (http://www.micheledelbecaro.com/tourist/egypt/templi-egizi/kom-ombo-11-.jpg.html) seem to be a little desaturated if you compare the images with the original (http://www.micheledelbecaro.com/albums/tourist/egypt/templi-egizi/kom-ombo-11-.jpg), why this? how can i avoid?

http://www.zenphoto.org/news/problems-with-albums-and-images#images-have-wrong-colors

ok i should try ImageMagick but my server use an old version (6.2.8), can i install a new one in my client side?

Imagick is server side, so you need to ask your host. But why not follow the advice to setup the images itself correctly?

uhm my photo are photoshop elaborated and saved with jpg and icc profile adobe rgb 1998, must i convert all image in srgb?

Yes ;-)

ah you killed me eheh

You do understand, don't you, that the WEB is primarily sRGB. Few browsers even honor colorspace profiles. Certainly the GD library does not. Maybe Imagic would, though. I don't know.

yes I was joking , i already started the conversion, thank you for the patience