@deadwood
MultiView automatically detects if DTWM_IFF is enabled in Picture Datatype.
But DTM_Write needs to be enabled in picture.conf file just below DT_PRINT on line 43. Add:
DTM_WRITE
.function DT_Write
If it isn't already enabled.
I was looking at your repository at:
github.com/deadwOOd/AROS
if that is the correct location for the current ABIv0 sources.
It seems DTM_WRITE is enabled. Mazze had enabled it in ABIv1 some time ago but he didn't have the Save ILBM for DT_Write. The current version of Picture Datatype for ABIv1 is 41.6 and yours is 41.5 so they are very similar. Just add the new DT_Write and two new methods (attributes). WhichPicture, GetNumPictures. DT_Write is already present at line 1604.
I included IFF Sample Images here as attached file.
You can also open 8bit or 24bit images in MultiView and Save As IFF. I can help test Picture Datatype and MultiView after you integrate the changes.