As you may have figured out already, the "lip" of the frame will cover up a small amount of the picture, so make sure important parts of your picture will not be obscured!
Measuring a picture
You may want to measure vertically and horizontally as shown on left.
Alternatively, it might be a good idea to get some paper and cut out an oval shape based on the standard sizes and hold it over the picture to see how it looks. Don't forget to subtract a little for the lip, which is approximately 5/16 inch plus or minus.
Be careful not to damage your picture! Also, it would be a big mistake to cut into your picture until you actually receive your frame.
Sizing of nostalgic frames
All our frame sizes refer to the inside opening, regardless of the shape. The opening is measured at its widest points on the back of the frame. The size refers to the opening taken at back the frame.