Hi,I am creating a room. There, I put a picture on the wall. I want that this picture looks like there is glas in front of it, so there should be some reflection. I managed it ones, but I lost the file. Whenever I do it now, the color of the picture looses its intensity, or there is no reflection.I can’t upload here, so I put the links from my dropbox.1. How it should look like (from the file that I lost)https://www.dropbox.com/s/vy1fiv6tprgr6rp/Zimmer_2015_05_07.jpg?dl=02. How it looks like now.https://www.dropbox.com/s/77ckjmg750mnujc/Zimmer_2015_05_16.jpg?dl=03. The settings I use for 2.https://www.dropbox.com/s/r8z6mdqxxd6au8d/Bild_einstellungen.jpg?dl=04. The .blend file.When you click the link, you will find a .jpg file.But it is not a .jpg file. It is a .7z file. Just remove .jpg and write .7zI hope I explained it good enough. English is not my mother tongue 
I don’t think it’s because of the the picture. Everything else is darker too and there’s no reflective light bouncing back to the pillars in front of the window. That would mean you have 0 or 1 bounces set in render properties. I can’t see those settings so maybe check those first and then go from there.
Also don’t write everything on one line, use paragraphs for subtopics. That way it’s easier to read and easier to split the message if someone wants to respond some part of the post.