'NoAttachmentPreview' Hides Attachment Previews From Notification Banners
Whether you just want your banner notifications to look cleaner, or you want to hide attachments from your banner notifications so that they’re not so easily visible by those around you, a new free jailbreak tweak called NoAttachmentPreview
by iOS developer Terry174 might be worth taking a look at.
As shown above, what the tweak does is it hides your incoming attachments, such as photographs that people send to you via text message or iMessage, from your banner notifications.
You will still see the text content of the message in your notification banners, but without the attachment preview, no one around you can see the attachment that is included with the message, which gives you more control over your privacy.
If you want to give NoAttachmentPreview a try, the tweak is available for free in Cydia’s BigBoss repository. NoAttachmentPreview doesn’t have any options to configure.