What is the purpose of content previews?
An example of content previews is that you have a list of news articles all with different stories, in the list is the name of the article and then 2 lines of truncated content. An example can be seen on the LEFT side of the image below:
My context: We have a list of different reading material, right now we show the material title and the first 2 lines of material content. The user then has to tap on the content to open the full view. One stakeholder in my project thinks that we should save space and remove the 2 lines of content preview.
It depends quite a lot, for example where I read my news I only have access to the title.
Lets take for example fairy tales on a fairy tales website. We have a title "The big bad wolf". Showing a preview of "Once upon a time" won`t bring any value to readers. But an image will certainly do.
So it depends from case to case, what you really need to find is the root of this. What kind of preview am I using and how it helps a user. Maybe you are publishing some documents and it would be useful to show as a preview the file type and size of it.
Another example would be listings, instead of showing a text preview under the title a image speaks more.
So yes, in my opinion you first need to figure if the user does really benefit in your particular case.