When any block-shaped items are placed into item frames, they appear sideways. The blocks face left initially, and rotate as if the side facing the player is the front. This is especially noticeable in items such as the furnace and jack o' lantern.

The image against wooden blocks below shows the issue in Minecraft 14w04b.

The image in the super flat world against cobblestone shows how the situation normally should occur in Minecraft 1.7.4.