Rated 4 out of 5 stars

by skierpage on Oct. 29, 2024 ·

This extension stops a large image from extending horizontally outside the message window by adding max-width:100% style and removing the width and height attributes (but they still appear in Image Properties > Dimensions). This is usually what you want, but not always; e.g. if you want to include a high-res image but make it appear smaller by reducing its width and height.

I filed mozilla bug 1927353 that Thunderbird "can't set inserted images to fit window without distortion". The CSS for {min,max}-{height,width} is extremely flexible and you can add it in Image Properties > [Advanced Edit] > Inline Style, but because you can't remove the width and height attributes, it's very hard to get Thunderbird to do the right thing.