Since the text screen area is marked as inuse by the system, ProDOS can not load the saved screen shot.
A solution makes that memory show as free while loading the picture:
10 A=PEEK(48984) : REM save the current memory bitmap area
20 POKE 48984,192 : REM Tell ProDOS that the Screen memory is not used
30 PRINT CHR$(4);"BLOAD IMAGE,A$400" : REM load in the screen file
40 POKE 48984,A :REM and put the bitmap back the way we found it