generate documentation dialog layout is wasting too much vertical space

[lhein]

The route image is simply too large for the amount of content displayed. Can we reduce the height ?

[igarashitm]

One option is to "centering" the diagrams when the preview modal is opened (note that centering automatically happens when visibility is changed) by Reset View action.

Otherwise, standard markdown doesn't have a way to specify the image size. The layout concern is left for the downstream document processing.
https://stackoverflow.com/questions/14675913/changing-image-size-in-markdown