Processing two images with different starts

I have 2 images with the same size but with different starts. I want use one as a mask.

Should I use import image filter first to set the same start for both of them?

You don’t need import filter. Updating the regions’ index can be done on an ITK image. But you should figure out whether that is the right thing to do - visualize for the image and mask together in Slicer to figure it out.