Hello Maher,

Try using the faceted search to preview items.

Just below the Activity Stream and Application Tabs, you will see the "Filter by" option. This allows you to filter the Activity Stream or the any other application view by simultaneous multiple parameters or facets, such as contributing users, content types, tags, date ranges or simply type a search term to find related results.

To search for images, go to the Image Gallery view and apply the filters to search. You can do the same to search for videos or audio files, and expand the result to quickly preview the video or audio right there.

Let me know if this helps.

doesn't this restrict the search to a single space or can I do this across spaces?

No.

The Activity Stream of the Home Space aggregates content from across all spaces in your Cyn.in site. This means you will be able to see and search from all the content from Spaces that you as a user have access to, in the Home Activity Stream.