The more text you put in a legal document the more loopholes there will be in it unless you are an expert in thinking through and writing such things.
If there is a sole purpose for the images you need a release for, then its simple to write a release for that sole purpose and nothing else.
If you want to use it for other purposes then those will need to be specified as well. That's where loopholes start to creep in, so it's easier to make the release all encompassing and then put in exceptions to that all encompassing release.
So it depends, on which way round it will be easier to write the damn thing without it being long and wordy.
Since you seem to want a limited release, then I would suggest you just make it clear that the release is for specific purpose only.