So you want people to make the objects for you? Or you want parts of existing art you have to buy?

If you are the person taking the pictures of the objects, you would own the copyright to the image. You could license the images however you wanted. There are a few exceptions to this, where you being the photographer would not make the images legally safe:

1. A person's likeness - basically, if there are people in the image and they are recognizable, you do not own the rights to their likeness. This is especially true for celebrities, since so many people could recognize their face and their likeness is what they get paid for.
2. Trademarks - taking pictures of the giant Coca-Cola sign in Times Square subjects your picture to Coca-Cola's trademark. Similarly, taking a screenshot of The Legend Of Zelda gameplay doesn't allow you to share the screenshot under whatever license you want since the characters displayed in that screenshot are trademarked by Nintendo. Could you use the screenshot under Fair-Use? Sure! But you couldn't share it under a specific license of your choosing.
3. Restricted locations - Laws differ on this from country to country, but in the US, it is illegal to take pictures of prisons, high-security military installations, etc. Disseminating such photographs would likewise be disallowed.

I hope that helps. :)

I think it is definitively NOT a silly idea to create a picture collection of items, windows, wood surfaces etc.

But I don't understand your question very well. Can you elaborate on what you are going to try?

For example: Which objects and wherefrom do you want to collect? And have you looked into databases (like this site here) already? And what purpose (for games? for your games? for videos?)

Greetings

Peter