If the applet is resized for example with 'document.getElementById("jmolApplet0").style.width = 1600' and 'document.getElementById("jmolApplet0").style.height = 1600' and then resized back to the original size (600x600), the second resize is not fully recognized internally. The applet is resized but the model shown is not adapted automatically to the new size. And if an image is requested with the function "jmolGetPropertyAsString("image")" it still has 1600x1600 pixels.
This problem is demonstrated at the following URL: http://www.fli-leibniz.de/cgi-bin/3d_mapping-resize.pl?CODE=1deh&JMOLVERSION=11.1.28
After loading the page first resize the graphics window to 1600x1600 pixel, then resize it to 600x600 pixel and generate a snapshot with the "snapshot" button.
It seems to work properly if the second resize is not to the initial size.