How about framing them with an attic window? You could use border prints too. You could get creative by appliqueing frames around each picture in different sizes and arranging them on background fabric to look like a wall collage of ladies in bonnets. Just an idea.
Sounds like you have an embroidery machine that you were going to use to "embroider" frames around the pictures. Look for separate patterns that have straight and corner pieces. That way if you have an embroidery program like 3D 4D or 5D you can create your own frame size by adding the separate elements.
Good Luck!