Feature Images

Hello,

When testing the speed of my website I have this error :
The following image(s) are missing width and/or height attributes.

Almost all images referred by the error are feature images.

Which file should I look to put the height and width attribute ?

What’s strange is that my feature image is 128×128 (desired size) and the theme looks like it’s resizing it anyway. What’s should be the default size for the Feature image ?

Thanks,

Benoit