Heidi Klum's Topless Photo RUINED By Designer Zac Posen's Hand

Heidi Klum nearly posted one of the best photos in the history of Instagram ... if only designer Zac Posen had kept his damn hand to himself.

Klum, wearing nothing but a pair of tiny panties, posted the photo with the caption: "@zac_posen ....I need something to wear for tonight's @projectrunway @lifetimetv."