The preview of the image before posting lets me know whether the picture is distorted or not. So I make the incremental adjustments of the size after seeing what side of it is off. I learned HTML 3.2 nearly 20 years ago and I’ve not kept up with the other versions. So I always add height and width dimensions and I use quote marks for everything. Thanks!
Yeah, the conventional wisdom was that you should specify an image's height and width so that the browser can proceed with the screen layout without waiting for the image to download, leaving an empty rectangle just large enough for the image. Later, when the image arrives, the browser can fill in the rectangle, resizing the image if necessary, and leave the rest of the screen layout undisturbed. If you don't specify the dimensions, then the browser can't know them until it receives the image, at which time it has to pop the image into the layout, causing things to jump around on the screen.
However, I've found it doesn't really matter that much.
Usually, if I specify a dimension, it is to achieve a layout objective. E.g., if two images are to be side-by-side, then I might force the taller one to the height of the shorter one. If they are to be stacked vertically, then I scrunch the wider one to match the narrower one. If the image is simply unreasonably large, then I might choose enforce a reasonable width. Or, ideally, resize or crop the image offline and post the modified version (saves bandwidth). Or google for an existing more suitably sized version.