I used 12 images with dimensions of around 800-1200 pixels each.
I made an article and for each image, in the Image Manager inside the article, I put only the height. For example 300 pixels. I saved and after some hours I saw the article live and realized that images do not resize in 300 pixels (with the corresponding height) as they should. Instead, they are displayed as full size!
I had to set both width and height to 300 so that my images will work! As a result, I uploaded an article, which on the editor looked normal (images looking to have 300 pixels size)
This needs to be fixed so that putting only width or only height should display the image normally.
Also this was tested in Incognito browser.