I use the same specific sizes for all my images in all my section editors to optimize for Bootstrap breakpoints and already adjusted the media library to match those values. I also take advantage of the picture element for a good responsive design experience.
Not all the images start out the same size. I resize all imported originals to 1920x1920. The image may be smaller than this but I never want them bigger. My thumbs are then set to
If I need to have a difference size say for a bio photo, I use a different upload field with different specs.
My section editors all have 'image' upload and 'document' upload. Some have a 'photo' upload and 'banner' upload. This setup allows a great deal of flexibility with very little overhead.
I have developed my app with modules for bios, blog, events, real estate listings, site owner info, ads, testimonials and several more. I can turn modules on and off for specific clients. All my configuration is done using yaml files.
I have approximately 35 clients using my app and am continually adding new options as clients request them.
The media library is a great addition, now I just need a document library for PDF files.