From a recent issue of Nature Cell Biology, here's an article on issues in displaying gels in a publication.

GEL SLICING AND DICING: A RECIPE FOR DISASTER
http://info.nature.com/cgi-bin24/DM/y/eOY60BhQ1V0Cs0KlP0Ay

The main points from the essay are:

"Display conservatively cropped versions of gels in the primary paper. A reasonable guide is to retain about five bandwidths of background above and below. Crop only when no essential information is at stake.

As far as possible, include essential controls and molecular-weight markers; either in the main figure or as Supplementary Information.

Avoid splicing different gels together. If unavoidable, clearly demark the point of splicing and avoid overextending quantitative interpretations across splices.

Display all of the key data involving cropped gels as a full and un-edited version with appropriate labelling in Supplementary Information; please display all panels as a single figure and refer
to this data in the relevant figure legends. As a minimum, provide un-cropped data at the submission stage to facilitate peer review."