Looks like everything is not working as intended after all 
I noticed that a frame was “subtly” longer than the others and I decided to add the frame number directly on the image (in red), while the frame number in code is displayed in blue… (as well as the offset and the timer)
As you can see, the image 1 appears twice in a row and the last image (5) is ignored… (while in code the frame numbers goes from 1 to 5 as expected)
I thought “offset = 1” would display the last frame, but does it mean that it displays the 1st frame instead (just like “offset = 0”) ? Like a loop or something?
Or is something just wrong with my calculations or how I understand/use this function? 