CorrectIlluminationCalculate without LoadImages cycle

I am trying to make an illumination correction matrix of large batches of files using CorrectIlluminationCalculate.
This module can calculate such a matrix at the very first cycle, taking images of the LoadImages module as input.
However, after that first cycle, my pipeline continues looping through all the LoadImages of the remaining cycles, loading around 15000 images, without doing anything with them.
This takes a lot of time, so I was wondering whether there is anyway to prevent that?

The alternative is to set “Calculate function for each image individually…” from “All: First cycle” to “All: Across cycles.” It will still loop through all the images but will accumulate the images for the illumination function as it does so, which should save you some time. One note: when you use SaveImages in this case, you will need to set “Select how often to save” to “Last cycle.”