Content type delete design question

Hello Friends,

Presently Our intranet site,Image library contains Images,Videos and Audio.I have requirement to delete the content type videos and audios.User must publish the Images only.I wrote powershell script it is deleteing the videos and audio content type in Image library.

One situation it is failing when Images library contains the videos or audios that time it is not able to delete content type because the some one alreay upload the videos or audios that why it is not deleting.

There is any why we can keep current content (eg audio or videos) delete content type in images library.

Thanks

for help

hk