Comment 2 for bug 1217752

Reproduced with r12487 on
- Ubuntu 12.04 (VM 64bit, inkscape-trunk from PPA)
- Ubuntu 13.04 (VM 64bit, inkscape-trunk from PPA)

Not tested:
- Ubuntu 12.10 (VM 64bit, local build):
  on Raring, raster extensions in stable 0.48 and trunk crash (in /usr/lib/x86_64-linux-gnu/libMagickCore.so.5)

Steps to verify that the extension itself works as expected:
1) launch inkscape (default prefs, default template)
2) import a bitmap image (embed)
3) select image, from the context menu open 'Image Properties…'
4) delete values for width and height (do NOT move or otherwise edit the image afterwords)
5) apply (or preview) e.g. 'Extensions > Raster > Wave…'
--> works as expected

6) undo (or toggle off live preview)
7) select image, nudge it with arrow keys
   (-> width and height values are regenerated automatically)
8) apply e.g. 'Extensions > Raster > Wave…'
--> extension fails (bitmap image appears unchanged)