Creating your own microlensing image is easy! The first step is to make sure your python installation has numpy, matplotlib, astropy and scipy installed. If that is not the case for you then follow those links to install them.
The next step is to download the microlens_image.py file and put it in a directory which you know how to access. Then simply run the file with:
python microlens_image.py <input_image> <output_image>
For example:
python microlens_image.py input.jpg output.jpg
Where input.jpg is in the same directory as the microlens_image.py file.
The code will then load in the input image, apply a microlensing effect to the middle of it and save the resultant image to the output_image location.
If you are looking to explore creating your own Galactic Underworld then see the StellarMortis repository.