Request to add low RAM option for sdxl_gen_img.py

For unknown reason, it appears that the latest version of changes affected the amount of RAM required for loading models in sdxl_gen_img.py and it is causing the script to run out of memory and stop.

Unfortunately, the lowram mode of sdxl_train_network.py is not available to reduce the peak RAM usage in low RAM enviroments such as Google Colab. Can it be added?

Start by reading sdxl_gen_img.py and compare its model-loading path with the lowram mode in sdxl_train_network.py. Trace where peak RAM usage occurs during loading and define the option's expected behavior for low-RAM environments such as Google Colab. Done means sdxl_gen_img.py provides an equivalent low-RAM mode without running out of memory.

Written by the indexing model from the issue text.