How to get uniform bubbles in simple dutch oven bread?
Given that the second picture is what you desire, your bread is over proofed. The large irregular bubbles and flat or sunken overall shape is indicative of such. There are a couple of things you can try:


Make sure to form the loaf such that it has a nice taught skin on the outside prior to final proofing. You will notice in the second picture, the bubble structure is obviously interrupted from where the loaf was folded inward onto itself to stretch the outer skin tight. (Note the concentration of large bubbles towards the lower mid-left of the loaf)
Don't let your bread proof for so long. Typically the longer the proofing period, the bigger the bubbles.
Punch the bread down more vigorously between proofings. This helps to pop the bubbles that have gotten too large.


That said, I would much rather eat the first loaf of bread, as that open structure and sturdy crust is what a lot of us home bakers enjoy most.

Extra Credit:
If you want your loaf to be tall instead of flat there are a few other things to try.


Develop a stronger gluten structure by kneading or stretching.
Make sure to form a taught skin around the outside of the dough when shaping the final loaf. This will help to constrict the outward spread of the dough.
Use a structured vessel to support the dough during the final rise. If you try to make a loaf like the one pictured on a flat surface, it will inevitably spread out and droop. Cheers!