remove redundant creation of ImageOptim in image_optim_spec
remove redundant creation of ImageOptim in image_optim_spec

mihailim/image_optim,ramiroaraujo/image_optim,ramiroaraujo/image_optim,weheartit/image_optim,weheartit/image_optim,toy/image_optim,toy/image_optim,weheartit/image_optim,toy/image_optim,ramiroaraujo/image_optim,mihailim/image_optim,mihailim/image_optim