I’m going to ask this again since my question got lost in all the posts since then:
This is a question for all of you.
http://usurpador.blogcindario.com/ has stated that the image for the Bomford BC was uploaded on 8/3/09.
How can someone know this? I didn’t realize that folks could see when a file was uploaded unless they were the ones doing the uploading and noted the time and date in their FTP client.
How can someone know this? I didn’t realize that folks could see when a file was uploaded unless they were the ones doing the uploading and noted the time and date in their FTP client.
You're correct. You can't, unless the server is configured to allow access to the directory listing via HTTP or FTP. I don't believe that's the case with the Bomford site. Whoever it was who made the claim simply mistook the time/date stamp in his download directory for the document creation date.
Frankly, a lot of the comments on this thread have make my teeth itch just to read them. This whole thread is dumb. The differences between the two documents in the OP were obviously caused by JPEG artifacts resulting from one of the being a low-res copy.
You can't necessarily tell when a file was originally uploaded. But, you can tell when any static HTML file was last changed on the server.
By default, your web browser caches static files (images, html, text, and anything not dynamically generated) in your temporary files. If you reload a page that contains those static files -- either by returning to it with the "back" button or entering the URL again -- your browser will check to see if the version in your cache is valid. Note that hitting the reload/refresh button generally bypasses this check and reloads all files.
The web browser checks for validity by providing the modification date/time the copy in your browser in your cache. When the file was originally downloaded, this information was included in the reply. This modification date/time is included in the request for the file.
If the modification date/time of the file in your cache matches the modification date/time on the server, the server simply responds with a 304 status (not modified). The browser knows it can substitute the cached file and not download the entire file again. If the modification date/times are different, the server transmits the new version of the file.
You can see this information in Internet Explorer by right-clicking on the image or static text and selecting "Properties".
In Firefox, the static web page info can be viewed by right-clicking on the page and selecting "View Page Info". If you want to see info about a particular image in Firefox, right-click on the image and select "View Image", then right click on the resulting webpage and select "View Page Info".