convert your stills to mov in the same timeline codec, re-import that mov back into your FCP timeline replacing the stills and then create a new XML
convert jpegs to tiff, make sure you have a sequencial number of frames, ie
bring them back into your timeline in FCP replacing your jpegs and then create a new XML..
problem with this is no timecode with tiff so make sure you have separate sequences for each and are unique in naming.
That should do it ...
Davinci Resolve Control Surface
Cubix desktop 4
2 Red Rockets