I have spent some time playing with MCDEdit, I have version 1.1 from volutar, and PckView version 1.5, downloaded from github and compiled.
MCDEdit seemed to work fine if all I do is replace the image with PckView and the MCD data with MCDEdit.
I ran into a problem when I tried deleting images and MCD data with MCDEdit.
1. I copied the mcd/pck/tab files for U_Walls02
2. I deleted items which were not walls, including the navigation terminals which are treated like walls
3. I saved the files with MCDEdit (mcdedit_window.png)
4. I opened the modified file with PckView and all of the images of the original file were still there (pckview_window.png)
Is there a step I'm missing with MCDEdit?
Ignore this post please, I figured it out.