In Fleep, you can configure your link previews setting per conversation, and for your whole account.
Link previews in a specific conversation
To turn link previews in one specific conversation on or off, open the Conversation Settings and configure the setting accordingly.
In the web app:
In the mobile apps (iOS on the left, Android on the right):
Link previews in all your conversations
To turn link previews on or off for all of your conversations, configure the setting for your whole account accordingly.
In the web app, click on your profile in the bottom left corner of the user interface, and choose Preferences from the popup menu. In the view that appears, tick or untick the checkbox in front of "Show link previews in message flow" accordingly:
On mobile apps, you can find this under Settings (iOS on the left, Android on the right):
Note that if you have enabled link previews for your entire account - then the per conversation setting will apply. If you have disabled link previews for your entire account - then the per conversation will have no effect in practice for you, and you will not see link previews.