Hi hirot,
Are they actually printing on a paper large enough to fit an entire 5500x3880 image? Because if not, I would strongly recommend resizing the images, not in PSM, but in an image editor like Paint or any other, and make the image no larger than the size that it needs to be on the paper. 5500x3880 is extremely large, and I can imagine that it could cause serious performance issues, especially if you have multiple layouts each with an image like this. (remember that these images are dynamic, and will therefore be reloaded on every record. Having to load a 5500x3880 image on 10 layouts for each record will be very slow!) The older version might have been lighter in terms of resources required to run it, and that might be why it didn't run out of memory, but I imagine that it was still a slow job to process. I believe that resizing the images will not only eliminate the out of memory error, it will also make the job faster to process.
Regards,
Raphaël Lalonde-Lefebvre