Gimp opens too big for the screen in Ubuntu 12.10?
Solution 1:
If we had the same problem, I could be available to reset the Gimp size by
Edit >Preferences > window management and clicking '" reset saved window positions to default value' ".
Source
Solution 2:
Ran in to something similar: the window was too tall, and I couldn't resize it vertically. It turned out that the tool pane on the left was fixing the window to a minimum height.
Increasing the width of the pane (hover over the area between the tools and the document, click drag to the right) allowed me to resize the window.
Solution 3:
This appears to be a known bug, intended to be fixed in version 2.10.