I redesigned my A5 picture frame for 10x15 pictures (4" x 6").
The frame is easy to print and easy to assemble (no glue needed, but it can be used if tolerances are not tight enough).
Once put together there is a slit on the side (or on the top if you use it in portrait mode) that allows for easy changing of the picture.
The stand of the A5 version works well if you want to use this frame in portrait mode. For landscape mode I added a new stand.
The author remixed this model.