Having a 1x1 option for PictureFrame is on the “to-do” list for V6. For now, you can determine the size of the bitmap and then size the PictureFrame rectangle accordingly.
FWIW here is a python script for V5 that checks the DPI of the imagefile and scales the pictureframe accordingly. PictureframeScale1To1_01_cmd.py (1.0 KB)