So you messed with the old Picasso software (?) which is totally incompatible with Picasso96...Now you should get rid of everything what it installed.
It does sound like what happened. Picasso 96 works with no problems in OS 3.1. The old Picasso software does as well but not both together. The Picasso 96 installer has has an uninstall option and I would remove it completely. The old Picasso software will have to be removed file by file. The most important one will be the monitor file in Devs/Monitors. Next will be the Picasso library files in the Libs drawer. Then you will have to get the files in the Prefs drawers. The env-archive files are normally hidden in this drawer and you will have to go into the workbench menu with this drawer opened and change Window/Show/Only Icons to Window/Show/All files. An env-archive drawer will appear and you will have to delete the Picasso files which, as I remember, are in a Picasso drawer.
The Picasso II also works with Cybergraphix 4. I have partitions with both systems on both my A2500 and A4000. Comparing them is like apples and oranges. Both have advantages and disadvantages. Picasso 96 is faster and easier to program screen modes with but Cybergraphix is more like native Amiga modes with dragable screens. It also can do Deluxe Paint IV AGA and Deluxe Paint V in 8 bit RTG modes. If you try that with Picasso 96, it just crashes.