do not compress just zip files in command line
With regular zip:
zip -0 -r mydirectory.zip mydirectory
This is what tarball archives are for.
tar -c -f archive.tar file directory/
This creates an uncompressed archive.
You can use the following command (taken from the 7zip docs):
7z a archive.zip *.jpg -mx0
It should be available via the p7zip-full package.