The way I see it there are acceptable "enhancements" and there are unacceptable ones.
For us gardeners who don't have the top of the line cameras, it can be quite difficult to capture a scene that is anywhere close to the way it looks in person. My camera is a several year old Fuji E510. It's fairly easy to use and it was affordable for a digital camera back in the day when I received it as a gift. But very frequently my photos look too dark or worse, too bright. Sometimes when this happens I'll click the button that says "auto correct" and see if that makes the photo look a little clearer. I don't usually do this for photos where flowers or plants are my subject. Why? Because it feels like cheating to me. If I'm correcting a photo of a colorful flower it feels like I'm deceiving my readers into thinking my flowers are prettier than they really are. I have way less of a problem with altering pictures of buildings and hardscapes where we're beauty is not the focus.
I feel that color enhancement is only acceptable when the goal is to purposely distort the color, like the blue cosmos above. Come on! There are no Blue Cosmos! For a while I was posting pictures of psychedelic photos but I don't think I led anybody astray with my green tomato sandwich.
Other enhancements I'm not bothered by are "soft focus", cropping, zooming and Black and White because they are obvious changes that do not affect the beauty-o-meter.
To manipulate the color of a flower on a digital photograph seems like an attempt to increase the pretty-ness of the flower. The blue cosmos above is actually a Cosmic Orange one. The color is outstanding but if I manipulated the color of the photo from Cosmic Orange to, say Really Really Cosmic Orange, that would seem wrong. Sure, my readers would be all like WOW GINA HAS THE MOST BEAUTIFUL COSMOS ON THE PLANET, but that's not really my cosmos! At that point it seems that the photo is more like an art project than showing what my personal flowers in my personal garden look like. And at that point, why don't I just get some pictures of some whole other person's garden and say they are mine?
I'd love to hear from some people who publish their garden photos in magazines. Is it acceptable to manipulate the photos in the magazine industry?
And what about the rest of the garden bloggers who frequently post photos on their blogs? Do you manipulate your photos? If you don't, are you bothered by those who do?