To lighten yes but to totally change the look of the home no.  Ticks me off to show a home that looks nothing like the pics. 

I would to remove a garbage can.  I think it's ok.  Improving on the actual property would be a huge disappointment when someone actually comes to view.

Not in all cases, to clear or brighten yes, but to make it look like something it is not, then a big NO as you will only end up with upset buyers. 

Not if it crosses the line and becomes false advertising.

To what extent?  To where it no longer represents the product?  Is that is the case, McDonalds, and many others would have impacts too.  I think Photoshop is a good tool but cant be taken too far over the top where it no longer looks like or represents the property.

Photo editing is a tool that can better position a poor representation. Push the envelope too far and you risk that reflection on yourself. 

Charles Ross I think photos should be Photoshopped to improve contrast or exposure, but not to enhance the physical characteristics of the property.

Every photograph should be edited to provide the best quality.

only for clarity and brightness.... not to make a dump look like a flower garden....

To lighten yes, many years ago there was a crimial that actually could somehow figure out the security code to the house if there was a picture of the keypad and since then if there is a picture of it I blurr out the key pad. Just habit at this point.

Except for those things I would not edit pictures, I've seen photos when the agents removed outlets, or a hole. That is going to far if you ask me.

Charles -- it depends.  Removing a trash can from a photo is one thing(and acceptable in my opinion). Removing power lines is not.  

Yes, but not to structurally change or deceive. Removal of trash cans, cars in driveways, etc.; it's all good.