I'm looking for some pictures of diesel engine oil filter elements showing contamination (wear debris, glycol, water, etc.) but haven't had much luck searching the web. Does anyone have any pictures or websites that I can look at? Thanks.

I don't think I have ever seen anything like that on the web. I have seen many filters like that over the years, nothing special to look at. If it has wear metal in it you will see metal flakes in the filter media. If metal flakes are found in the media then use a magnet to see if they are ferrous or not. If it's coolant/water contamination and the level is high enough the oil will probably be milky looking. It's not to difficult to look at filter media and tell what it is your looking at. Besides, if you can see it in the filter media then your already at the critical/failure level and the equipment needs to be taken out of service.