If you have a Blogger web site, you may have recently found to your surprise and annoyance -- like I did -- that Picasa/Google+ has started auto-adjusting your photos upon upload. For me, this seems to have started today, when a photograph of a mountain trail near darkness was brightened in a way that had nothing to do with anything I had done. It was terrible. Typically I spend a good deal of time adjusting my photos to get them right, so this was disconcerting.
After some searching, I found a couple of posts about how Picasa Web, which Google was using to store Blogger uploaded photos, was transitioning to Google+ for photo storage.
I had recently activated some Google+ stuff regarding my account, so I poked around in my account settings and -- lo and behold! -- I found a setting for whether to automatically adjust photos or not. I turned it off, and my photos were back to normal on upload. Phew.
Go to your Google+ account settings, search for "Photos", and "Auto Enhance". I turned it off. I also checked "Upload my photos at full size".
I really despise default settings that are intended to idiot-proof a process. Because usually, they just end up making an idiot out of me.