a picture frame is formed by folding a unitary blank along pre - formed fold lines and includes front , intermediate and rear panels . the intermediate panel is folded behind the front panel , which is apertured , to form a three - sided pocket for retaining a picture to be viewed through the aperture . a pocket seal is effected by the rear panel which is folded over the intermediate panel and is also folded out of plane to present a convex rear frame surface . a resulting curved lower edge of the rear panel cooperates with the lower edge joining the front and intermediate panels to provide a stable support for the frame . the front panel is provided with flaps which overlie the intermediate panel to close the sides of the pocket . slots are defined in the flaps to receive tabs on the rear panel to secure the rear panel in its folded configuration .