Nothing is too silly to take a photo of. My own motivation to write has been driven by two elements. 1) The writers whose books I have been able to read in my lifetime and 2) the places I have visited.
I am sure many onlookers thought me insane when I was standing around the European countryside taking pictures of corridors, roofs and alcoves whilst they snapped the usual tourist sights. But when I look back at those photo’s now I find the spark that I need to bring life to my writing.
Never delete your old photo’s! Look back to them and bring the memories hidden in the corner of your mind back to the front. There are few better sources of inspiration than the real world.
Blotting Away 
My wife routinely takes picture of doors and windows, so if you’re insane, she is as well. Erm…yes.
Is this the door to the Room of Requirement?
I was afraid to go through the door, lest my hopes of it leading to Narnia be shattered!
Ah, but you can only find Narnia if you’re not looking for it, don’t you know? 😀