How to implement a gallery in Joomla?

Question

Joomla

The bottom line is this: there are a lot of pictures, they need to be placed on the page under each heading (2-4 pieces each)
Problem: pictures of different sizes, formats, aspect ratios
Question: how to implement them so that they are placed neatly and beautifully without interfering with their format using Photoshop ?
I partly solved the problem with the WidgetKit plugin (there you can create mini galleries for each heading and specify the size of the pictures), BUT it crops the picture.
And I need it to add a smaller picture on a white background, the size of which will be the same as the big picture and all the pictures in the preview were the same size and format (do not care about the scale).
Any ideas? Thank you!