All photos of him would have been taken before 1923 and thus are in the Public Domain so no need to worry about copyright. Though it would be good to add the source as a courtesy. Though some may ask if taking an image from another site of him infringes on their copyright, in essence, you can't claim a copyright on something in the Public Domain. If this were true, I would have copyrighted his books and be gladly taking royalties for any current printings.
The current photos of his study and grave marker are another question and these could have copyright protection afforded to them. Though the doctrine of Fair Use regarding copyrighted materials would probably permit their use with no infringement here, it would be best if the source(s) was posted to follow the doctrine's basic tenents.
The image of Stormfield is from a book published before 1923 and is in the Public Domain and does have a source.
The stamp is a US Government produced product and not liable to copyright protection.
Everything above is based on United States Copyright Law as the images are from the United States. Laws differ from country to country and each has its on rules one how long a copyright is retained and or how it is obtained.
All in all, sources should be acknowledged for any image just as any fact that is in a Profile. Just good genealogical form.
As to a search to find those without accreditation, I'll leave that to Aleš. LOL