Imageconverting with ImageMagick

I need a script which - handles large jpeg files, - rename that file to uniqueid(), - create from that file a high quality copy in max. 640px (the embedded ICC-profile should stay in that new file), - create a copy from the 640px file in max. 360px with a ICC-profile of sRGB in it (a colorspace transformation) and watermark it with a given png-file - create a copy from the 640px file in max. 120px Each file has to be moved to a separate directory and each file has the same name! All has to use ImageMagick 5.5.7 as I do not have version 6 installed! In have to integrate that as a function into a script which I already have!