Based on the information provided I visited the Fujifilm page and found three products that are within the size range given. (3.25" X 4.25")
FP-100C Color ISO 100
FP-100B B/W ISO 100
FP-3000B B/W ISO 3000
I'll buy a pack of FP-100C just to try it.
Thank you all for the information provided.
Very helpful indeed.